Zoo Med said not to use a Reptisun T5 in my cage. Thoughts?

Hi. This question seems to involve multiple categories so I wasn’t quite sure where to post it. Here goes:
I own two bearded dragons, and each is housed in their own 4x2x2 enclosure that features a Reptisun T5 10.0. I recently got an opportunity to acquire several very nice and nearly new cages from a well-regarded company (Animal Plastics) from a reptile breeder that’s retiring soon. The dimensions of these very beautiful cages are the same as my current enclosures except for the height. The cages are 15” high, and I was wondering if this would be suitable for a beardie. Because the Reptisun T5 is an intense UV light, I contacted Zoo Med to ask for their perspective on the potential lighting situation. They advised me that a T5 10.0 would be too intense for this height and could result in potential health problems down the road (their statement that the Reptisun T5 10.0 isn’t universally suitable for all enclosures and could have potentially detrimental affects on a beardie if too close feels like it could be its own thread/discussion on this forum. I’ve posted their full response below in case it’s helpful). So I was advised to purchase a T8 if I did decide to purchase the new 15” high enclosures. I don’t have any experience with the T8s, and so I have a few concerns I was hoping anyone with a deeper knowledge of T8s vs. T5s could help me with so that I can make a decision whether to snap up these gorgeous deeply discounted cages or take a pass and stick with 24” high cages for any future beardies. I’d really love to make these cages work so any advice would be much appreciated!
1. A Reptisun T5 10.0 is one of the UV gold lighting standards, but would a T8 that’s in a 15” cage work equally as well (aka does the closer distance make a T8 comparable to a T5 that’s farther away)? I don’t mind replacing the T8s in the 15” cages more often than the Reptisun T5s in my other cages as long as the T8s produce a sufficient amount of UV.
2. Does anyone have an enclosure 15” high or in the ballpark of that height? If so, have you found it easy to light/heat/ furnish? One of my beardies loves to climb as high as you’ll allow her to while the other seems to prefer staying close to the ground. I suppose a 15” cage just requires a bit more decor planning to maximize space and ensure the beardie isn’t able to get close to the basking light. If anyone has suggestions for the best way to set up a cage of this height (or better—pictures) I’d love your thoughts.
These cages are typically fairly expensive so I’m being offered an incredible deal and want badly to snap them up, but only if they won’t compromise the quality of life for the beardies that will live in them. And if anyone has any experience with Animal Plastics I’d love your opinion on their cages. Thanks to anyone that can offer their advice and help me make a decision!
Zoo Med’s email response when I asked what a lighting recommendation for this cage would be:
“Thank you for contacting us. Being the first company that created the UVB bulb in 1993 we are the only company that recommends replacing our bulbs every 12 months, everyone else is six months. Both the T8 and T5 UVB bulbs will produce UVB for up to 12 months, however the output is going to be different. The T5 bulbs bring HO produce UVB that reaches further then the T8 bulbs. If your enclosures are 14-18 inches tall then I do not recommend using a T5 bulb inside them. Using a T5 HO UVB bulb on the inside of those enclosures may overexpose your bearded dragon to UVB which can cause health issues. If you get the 14 inch tall enclosure use the T8 5.0 bulb in it, if you get the one that is 18 inches tall you can use the T8 10.0 bulb in it.”

I'd think its entirely fine to put the reptisun t5 10.0 bulb inside. For quite some time my juvenile was in a 20 gallon with screen only over the basking area to hold her heat lamp, she had a reptisun t5 ho 10.0 46" uvb bulb going across her tank and another tank. There was basically nothing blocking the uvb bulb, it was 10 inches from the bottom of the enclosure or around there and was in a reflective fixture and she was in there for 4-5 months or so. She did entirely fine.

Also the difference between the t8 and t5's is that the t8's are quite weak and the beardie needs to be able to get within at least 6-8 inches of them. While t5's can produce good uvb down to around 12-14 inches or so. I'd just continue using a t5 10.0.

Also the, "we are the only company that recommends replacing our bulbs every 12 months" is pretty false. Arcadia, one of the best for uvb lighting, basically most of their bulbs last 12 months if possibly longer than a reptisun.
And from what ive seen if you used a t8 5.0 it would barely be enough uvb for a bearded dragon to live healthily.
Personally I dont trust what many brands say without evidence of it.

I agree with the last post. The key is to build as much variety as you can. Offer high levels of UVB but also build some areas with low UVB. This is the same as with heat. 15'' is a short tank and keeping UVB lighting at an appropriate distance will cost climbing area which is detrimental. A good compromise might be using a T5 5.0 22'' or a 10.0 without a reflector which should sit about 6-8'' above the basking area. That will let you build some climbs and a basking spot about 6'' up off the floor (giving 2'' of space to the light fixture overhead). Alternatively you could cheat the 10.0 (or Arcadia 12%) forward or backward in the tank. That will create a gradient along the width of the tank so the most intense UVB will be along the back of the basking area (or front) and allow you to build the opposite side of the basking area a bit higher. As long as everything is easily accessible and there is a good variety available, a dragon will know how to self regulate. You can observe their patterns over time and adjust lighting to optimize for your each individual case.

If you don't have a Solarmeter available to measure output (shoot for about 3-6 UVI in the basking zone) I suggest reviewing Taterbug's lighting guide. She put together some test results and shows different combinations of lighting and distances that may be helpful. https://sites.google.com/site/thelizardmadness/lighting-guides

A T5HO 10% - 12%UVB IN A REFLECTOR HOOD is PERFECT for a 2ft tall viv with a solid / timber lid/top , is the BEST PRACTICE / STANDARD for UV for bearded dragons here in AUSTRALIA .

Glass fishtank style vivs so common overseas are not recommended or commonly used here to house dragons of any kind , nor are mesh lids on tanks.

This will provide real information :
viewtopic.php?f=6&t=234801&p=1806497#p1806497
as will this
viewtopic.php?f=34&t=234800
and this
viewtopic.php?f=34&t=235611

The reflector hood will essentially double the UV at the basking spot.

Aim for 180 - 200 microW UVB / sq.cm at the basking spot ( a 12% UVB tube in reflector hood will give this at 30cm or 12in from the tube ) and 100 microW UVB / sq.cm ELSEWHERE.

Thanks everyone for the input! The UV links/charts were very interesting. The cage I was considering doesn’t have a mesh lid so any of the UVB tube lights could be easily mounted on the ceiling. In everything I’ve read about T5s I’d never come across anything that said they could be too intense or result in health issues if placed too close so I was very taken aback when the company that manufactures Reptisun told me to opt for a T8. They know I’m going to purchase a Reptisun from them no matter what model I opt for so it was surprising to see them guide me toward the older T8 model rather than the more expensive T5, which is what gave me pause and made me wonder if a T5 shouldn’t be a given for all enclosures. They make it sound like if I don’t use a T8 and instead choose a T5 10.0 for a 15” high tank I’ll essentially be sealing my lizard’s doom, so that email caused quite a bit of stress.

Yeah it's certainly not as ominous as they made it sound. Dragons can handle pretty intense sunlight in their natural range. It's just a matter of giving them a good spread of options since you're condensing a fairly large natural range into a small indoor habitat for them. There are a lot of things you can do to tweak the lighting/temps using different furniture and materials to fit an individual preference once you see how they react to the setup but I wouldn't worry about it being outright harmful in a tank that size.