Help with figuring out lighting in 40 gallon tank

I'm preparing to get a bearded dragon. I already have a 40-gallon tank (to probably be upgraded as it grows), have feeding figured out, and other requirements. But I'm getting so confused and frustrated over lighting. I initially wanted to use mercury vapor bulbs. I hear one thing from one site and then another thing from another and it got ruled out. So I landed on having to use a halogen bulb for basking and an 18" slimline light for uva+uvb requirements. But is that appropriate? Should it be bigger or smaller? What wattage should be used in a 40-gallon for slimline bulbs? And not only that, but is it really risky to use an mvb in a regular sized tank? I heard it was safe then was told by someone else that it wasn't so please help. Ugh :|

This is what is recommended on this board others can weigh in on the Mercury Vapor bulb--
Which UVB light should I use?
The best UVB light is a ReptiSun 10.0 fluorescent tube HO (Or Arcardia 12% in the UK). Compact or coil bulbs do not emit the proper amount of UVB light for a bearded dragon, and should not be used. Other brands, such as the Zilla Desert Series and ReptiGlo have been known to cause eye problems and other health issues with bearded dragons, and should be avoided. The reason that some UVB lights (Zilla, ReptiGlo, coils/compacts, ect.) are considered dangerous is because the wavelength of UVB that they emit is shorter and more intense than the wavelength of the "safe" lights (ReptiSun, Arcadia). UVB lights should be replaced every 6 months. The T5’s are a strong bulb and only need to be replaced once a year – the T 8 every 6 months--- where as the T 8 are not as strong—they need to be placed inside the tank the T 5 10.0 bulb approx 10-11 inches from basking spot – the T 8 approx 8-10 inches from basking spot—the cover needs to be off the bulb for full effect of the UVB rays-- you need a bright white basking bulb that keeps basking temps to 95-105 for adults and 100-110 for babies -- then tend to like it warmer --- if you need extra heat in the tank a CHE ceramic heat emitter is recommended - they come in 75 and 100 watt bulbs - they produce no light--- No colored bulbs please!!
Karrie

I agree that the T8 slimline is a bit weak for a 40g tank. Going with a 22'' T5 is a better choice. You can use that along with a halogen flood light for basking and it should work well. The downside of MVBs is that they don't have a very wide beam of UVB and you can't adjust heat independently from UVB output (height). I prefer using them as travel bulbs and for portable basking spots outside of the tank.