Welp, went ahead and bought a number of materials yesterday:
GE Silicone I Clear-Tub and Tile
Great Stuff Foam-Big Gap Filler

I'm fairly confident on the silicone, although after some reading on dendroboards I found that window and door may have superior adhesion to glass versus the Tub and Tile version, but I'm working with sterilite bins. The foam, on the other hand, worries me. After examining the active ingredients of both regular and the "Big Gap Filler" version, both appeared pretty much the same in terms of ingredients, so I have the big gap filler, because I figured the larger expansion would make covering the back easier, but in retrospect this may have been a hasty decision, seeing as I'm no foam expert. I also realized I didn't need to rush it on the foam, since I don't have to apply the foam until I finish constructing the tank itself. Should I return it and get regular, or maybe even just return it, wait, and get "Handi-Foam" brand instead?