Final viv upgrade - need help on lighting a bigger tank!

Hi all

My first post here. I'm upgrading Albus's vivarium to a 4' x 2' x 2'. As I'm doing this I'm also upgrading his lights (along with anything else I need to).

So far I have got an Arcadia T5 12% UV light (34", 39w), and a 100 watt halogen heat lamp. My main question is how far exactly should he be away from the lamps? Should I mount the UV lamp to the ceiling of the enclosure? If so it will be ~4" higher than the heat lamp, but I think they can sit closer to the heat than the T5 (I understand ~15" from UV and ~10-12" from heat lamp, is this correct?). So the basking area would need to be ~9" from floor of viv?

If I mount T5 to ceiling of viv would he be getting enough UV on the floor of the viv?

Thanks - sorry for so many Qs, want to ensure I get everything perfect as this will be his final enclosure!

That's a good UVB light and will work well anywhere from 10-14'' really. Ideal tends to be around 12'' but there is definitely buffer in those estimates. As long as he can move away from the light he can have areas that are closer. Same with the heat light. I like to keep those at least 12'' away partly to keep them out of reach and partly so they are high enough to cast a nice wide beam. As long as the basking temp area is large enough to allow for even basking and the light is out of reach and you're hitting a good surface temperature that's the main concern.