You'll need to be aware of a couple of things...heat output and light 'fall off'.

I would suggest starting out following the manufacturers recommendation and remember that fluorescent lights can and should be positioned closer to the subject than incandescent bulbs. If you find that the habitat overheats (more than 85F or so), then move the light away a little, but remember that having the light too far away will pretty much render it useless.

An ideal habitat (indoor or out) should have a temperature gradient (so the animal can adjust for itself) as well as light and shade.

Having one end of the habitat cooler and equipped with shady hiding spots will work.

Hope that helps.