I think plastic sweater boxes work better than aquariums, especially if you need to add humidity. I don't have a lot of snakes, so I keep them in individual boxes and not racks. I size the boxes so width length is greater than the snake length. Depending on how long and flexible the cover is, I supplement cover latches with inexpensive quick release clamps that they sell at home improvement stores.
I use Brandon Osbourne's trick of a step drill to drill holes in sides for ventillation. A few on the warm side, more on the cool side. I also drill holes in the cover on the cool side.
I use heating pads that I make by sandwiching an 11" Flexwatt strip between two thin 12" ceramic floor tiles. The heating pad is plugged into a dedicated receptacle controlled by a dimmer switch. I like to keep an 1/8" or so gap between the counter/shelf and the cage and the heating pad. I also install a dial-face temperature probe through the side of the cage near the floor of the warm side and one on the cool side to easily monitor temperatures. I can easily keep an 82 warm/76 cool temperature gradient with minor tweaking of the dimmer switch.
I like the plastic plant saucers for hides. I buy an assortment of sizes and cut an access hole with a Dremel. Snakes seem more comfortable with hides that almost look too small. I use one hide on each end and one in the middle for larger cages.
A heavy, wide water dish provides me with good humidity levels. So far, I have only had complete sheds in my collection. I like the white Corningware dishes for water, but there are probably cheaper alternates that work as well. If you need more humidity, you can put a water dish closer to the heating pad, but it can turn into a sauna.
For smaller snakes, I like white paper towels for substrate. You can keep the cage very clean that way. When they get bigger and messier, I think aspen probably works a little better.
I know there are a lot of different approaches out there. This is just what I've been doing. Good luck to you.
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Tim