That helped a little.
I don't have a light. I was just asking about a certain light to see if it was a good one. I'm using a UTH. I'm measuring temps with an Acu-rite thermometer/humidity sensor. Probably the exact same one mentioned in that FAQ.
The tub is 22"L x 16"W x 11"H
Yes it's a human pad. Once again I was told "That'll work fine" but of course it isn't and I want to make absolutely sure I've got a good system this time. And yes that does help. Specifically listing belly temp helps a lot. I was freaking out about getting the ambient temps to 90 degrees.