my suggestion is to use a piece of 3/8" Lucite for the divider, and 1/4" or 1/8" for the lid. The thick 1/4" would allow for careful drilling of holes for hinges to be installed for the separate lids. use small "craft" hinges, I dont know the actual name but like the kind you see on jewelry boxes. the measurements for a divider for a typical 10 gallon tank are as follows:
11-1/2 by 9- 5/8
you may need to make a notch at the top on each side of the divider that is about 1/4" long so that the top has a top that looks like this:
you get the idea, this will help insure that there is no gap between whatever you use as a top and the divider, learned the hard way. hope this helps
damn, that little group of lines was supposed to be a rough diagram of the lid profile, oh well. guess now its just to show im retarded. lol.
by the way, if you use 1/4" Lucite you can get it at Lowe's, Home Depot, or other places of that nature.
As far as drill bit and hinge screw size you may wanna go with a
1/16" bit and 3/32" screws and remember not to over tighten, and make sure that on the lid you mount the hinges in far enough to avoid cracking of the outer edge of the lid, im a little bit of a handyman on some things, guess spider houses really arent any different from any other "handy man" project. I am currently designing a terrerium for an A. avicularia community of about 4 avics.
oh, p.s., I just used plain ol' aquarium sealant, but since you arent putting fish in it, I dont see the harm in using clear silicone from the local autoparts, it has the same amount of "fuming" while using and curing. and its cheaper. lol=D