Quote Originally Posted by JamesMX39
1) What size tubs are good for an adult? I will provide hides for the smaller snakes.
32qt to 41qt Sterilite is fine for adult balls.

Quote Originally Posted by JamesMX39
2) How much flexwatt should go on the bottom of each tub to maintain a nice gradient?
If you're using 3" or 4" two strips along the back of the 41qt tubs, 1 strip along the back of the 32 qt tubs... (If the tubs are organized in a sideways fashion... (the most space saving design)

Quote Originally Posted by JamesMX39
3) I would assume that the top of the tub would have be flush with the bottom of the shelf above it. Won't this restrict all of the air flow? Should I drill holes in the tubs to allow fresh air to get in?
Yep. Soldering works best... Drilling and the pressure associated with drilling can crack the tubs.. so melting the holes with a soldering iron works best.

Quote Originally Posted by JamesMX39
4) You mentioned using foil tape and insulation. In what areas should this be used, and in what quantities?
As far as the foil tape goes, you can use the foil tape to tape the tstat probe to the flexwatt.

Quote Originally Posted by JamesMX39
5) If you answered this already, sorry, but I should cover the sides so it gets dark in the back, right? Seems like most of the ones I have seen have the sides enclosed, but as I was looking around I came across a few that weren't.
Enclosed racks are usually the most secure, but with hides in the tubs, it doesn't HAVE to be enclosed. Your BPs will enjoy the darker spaces towards the back of the tubs though.

Hope this helps!