That's wonderful that you are setting the enclosure up BEFORE getting the snake. Very smart on your part

The lamp would do well, or you can get a ceramic heat emitter since it doesn't emit any light, and you wouldn't have to worry about finding a suitable red reptile bulb. You could put the lamp in the center, and cover the rest of the screen top with Con-Tac paper or saranwrap duct taped to the screen. Both work well to keep humidity in. You could also get a 2 small pieces of plexiglass from Home Depot/Lowe's the size of the screen insert on the lid(leaving room for the lamp), and just lay it on top of the screen. Drilling holes in the plexiglass will help with ventilation. The ConTac paper(cabinet shelf liner) Glad Press N' Seal or Saran Wrap all work well in keeping humidity in. Lamps dry out the air and these are good ways to help counteract that.

How are you measuring temps and humidity now? A good digital thermometer that measures two temps(warm and cool sides) and humidity can be found at WalMart for $15. The brand is Acu-Rite, and it is found in the outdoor thermometer section, which is by the light bulbs/switches and behind the paint section. Digital is the best way to go when keeping ball pythons and any cold-blooded animal. If you already have a good digital thermo. then wonderful

What are you planning on using for bedding? Just a suggestion, but when you first get the snake, for the first month or so, I would keep it on paper towels or newspaper as those make it much easier to spot abnormal feces, external parasites such as mites, and are easier to keep clean. After that you can use cypress mulch(found at Home Depot in HUGE bags- get double-milled or shredded- costs around $3-bake it first to dry it completely and get rid of bugs), or you can use aspen shavings(molds easily with higher humidity-adequate ventilation is a must), newspaper/newsprint(easy to clean, can still look nice), ReptiBark(expensive, but works-can harbor parasites), Bed-A-Beast is OK if it is kept dry(pretty inexpensive and expands alot-needs to be thoroughly dried before use with these guys). Beddings I wouldn't use are pine or cedar ANYTHING, carpet(harbors bacteria very easily and is a pain to clean-very expensive at pet store-cheap at Home Depot/Lowe's), anything else that retains too much moisture such as soil, sand(gets in betwen scales and in heat pits/nostrils), gravel(bacteria factory, impossible to spot clean, requires everything be washed when snake has a BM).

What are you thinking about using for hides? Any other "furniture" you want to use? Ceramic pot bottoms/saucers work great for hides. They are low to the ground, heavy and dark. Ball pythons love them. The plastic ones work great also. You can find great looking silk plants/vines at WalMart/Michael's/Hobby Lobby. Those make great cover areas for the snake, making it feel secure.

I don't know what else I need to cover, LoL. If you have any other questions, just ask, I or someone else will be along to write another book, heh.

Good luck getting it all set up