Lighting for 4x2x2 cage??

[Smeagol358]

Hi, I have a 4 month old bearded dragon living in a 20 gallon long tank. When he out grows that I'm going to build a 4x2x2 cage with my dad. But the only thing that is bugging me is that I don't really know how many watts the lights should be. The lights that I am using noww are a 150 watt bulb for his basking stop, T8 15 watt UVB bulb (by Zilla) and a 60 watt infared bulb that i sometimes use at night when it gets really cold in my room. Will these lights be OK or should I get higher wattage bulbs??