Ok so I finished my rack. For a first attempt, Id say it isn't bad. I'm stabilizing the tubs one at a time, the one on the bottom has my Het Lavender who is already enjoying his new home. On the top shelf I have my normal female sitting in a pillowcase enjoying the warmth coming from the flexwatt thru the plastic tub lid while her tub stabilizes.
Wired the flexwatt in parallel, that was a good time. Thank you BP.net for answering any questions I might've had without me having to ask them. Soldering makes sense now, and everything looks good. I borrowed the hinge idea from another rack on here, which you can see in the first picture. It's not on a constant hinge, the side is actually screwed to the shelves...so I have to unscrew 5 screws for hinge door access. Hehe. Whatever.
Materials (wood, screws, tape, polyurethane, brushes) ~80
Husbandry items (thermostat, flexwatt)~150