Unfortunately, those enclosures are extremely hard to keep humid without some sort of misting system. I have one myself and I could never keep humidity without misting every 4-6 hours (that's with 50% of the bottom being water dish, wet towels on the top, cypress mulch substrate. I think sealing the top with a solid piece of plexi or glass and sealant can help humidity a bit, but that's a bit of effort.

I think using it with cypress mulch (not sure how eco earth stacks up humidity wise) and covering the top with wet towels and misting should get you into the ball python humidity range 50-60%.

If you are going to keep a herp that needs humidity, look into either that or get a cage that retains humidity better (PVC is generally the best).

As for heat sources, under tank heat pads are very popular for BPs as it allows them to just sit on a hotspot. I found I needed both a UTH and a ceramic emitter to keep the exo-terra in the usable temp range for BPs. You can also look into radiant heat panels which are more safe for reptiles typically due to a more controlled, gentler heat (heats up objects with radiant heat instead of just getting very hot).

Hope that helps! My exo-terra at the moment is just sitting empty as I couldn't find anything that I liked and could create a stable habitat for in there. Maybe you'll have better luck.