New Ball is not active at night

[tttaylorrr]

I say "ambient temp" but my thermostat is actually resting on the ground of the enclosure. I will definitely lower it a few degrees though.

the thermostat probe needs to be OUTSIDE the enclosure sandwiched between the UTH and the OUTSIDE bottom of the enclosure. a UTH DOES NOT affect ambient temps and is not an ambient heat source; you need supplemental heating, i.e. a CHE (ceramic heat emitter) to raise ambient temperatures if you're struggling to maintain temps.

One more question that I've been wondering, how much of the screen lid can I cover and still allow good air circulation. I probably have over half of the screen lid covered (including where the light sits). Is that too much? Could I cover even more than half?

you can cover the whole thing; stagnant air won't have any affect on the snake. if you're worried about circulation, use tinfoil or saran wrap to cover the entire mesh top and cut two slits into it with a box cutter or other knife and that will allow air flow.