You need a thermostat for that heat pad. Unregulated UTHs can/will get 110F or hotter which can burn or do neurological dmg to a boa. Also the substrate is way too deep for a UTH. You want about 1/4-1/2 inch deep. As deep as you got it, that UTH is doing nothing.

The CHE is to give heat with out light. You don't need a red light. But if you got a UTH and set it up right, then you will be fine without the CHE. I personally just use flexwatt only in my AP cages and a RHP in my Constrictors NW cage. I also only keep the aspen about 1/2 inch deep so the snakes can easily push it aside to sit on the heat if wanted.

Finally you say all the temps are "right" yet what are the temps when that daylight turns off? UTHs don't give much heat in AP cages. In a glass tank, it would provide 0 ambient heat and under what appears to be about 1-2 inches of Eco Earth, it would provide less than 0.