start with a 10 or 20 Gallon???

[guidofatherof5]

How are the Zoo Med Reptisun Terrium Hoods for light?

Zoo Med Reptisun Terrarium Hood Reptile Light Fixtures

Looks like it goes on top of the screen. Good and safe.
Save yourself some money and buy used as much as you can. Your snake won't care and the money save can be used for pinkies and other good foods for it. I've tried the store bought hides and my snake don't used then as much as a good old cardboard box. When your walking around Walmart or any other store and they're stocking shelves, ask for the boxes that would make good hides. Free is great.
With that being said, nothing looks nicer than a full blown setup that grabs your attention when you see it. It's up to you which way to go.