Hello,
Terrific, I'm glad to hear there is a Tractor Supply around. Most panacur is a standardized 10% in stores. If you get a large tube, you wont use much of it but you could keep it on hand.
I can help with dosing if you need, it should be paste form. Panacur is used for reptiles, mammals & livestock as a standard dewormer.
How is he doing today?
As far as knowing how long they have had worms, etc before it shows symptoms, that is very individual because some dragons handle it better than others. If they have low counts, you may or may not notice any effects but higher counts, you would see lethargic behavior, loss of appetite, etc. Since you have noticed he is bloated, then chances are they are affecting his digestion a little bit. So, if you treat early then they will get under control & he shouldn't have anymore trouble for awhile.
The Powersun MVB 100 watt has been a good quality light & is safe. It will need to be placed at or around 12 inches from him. While it isn't the strongest MVB on the market, it is safe. If you have enough room, you could add a tube UVB, such as the Reptisun 10 tube or the Arcadia D3 12%, for a more balanced UVB exposure.
The ceramic heat emitter can be used at night, no problem at all. If the nighttime temperatures don't fall below 65 or so then you don't absolutely need it. If you used an undertank heater be sure there is something in between him & the heater so it doesn't get too warm.
Tracie