about substrate, temperature, burrow and urine/poop absorb

[alice40604345]

Hi guys! I was treating my new baby Suriname boa with mites and thanks for all the helpful information I got from here, now three weeks passed and I don't see one mite on him, so I plan to change his substrate to Reptichip soon. He's living on paper towel now. However, I find some problems.
I just learned here that pythons will burrow so I should measure the inside bottom of the tub to be 90-94F not the surface of the substrate. Should this be same with the boa? Since the surface of the substrate will be only 80F if I do this, not sure do boas also burrow and find the comfortable zone? Since I didn't see heat sensors around their nose like ball pythons.
Besides, I find that if he poop or urinate, the paper towel is so wet in a large area so I don't like that. If I use reptichip, I find that many people say the substrate should be no thicker than 1/2 inches. So it would be only one layer and if he burrow and poop or urinate I guess I have to clean the tub instead of spot clean And maybe some poop will stick to the tub and the tub will stink...I wonder is there any good methods to solve this?
In the past I measure the surface of the substrate (89F) and I put thick Forest Floor under my ball pythons and they don't burrow. Now I know it's not secure if they burrow and they will get burned so I will not do that. But does this work for boas? And how thick of or what substrate would be a good solution for both the keep the surface temperature more similar to the bottom of tub and absorb their poop/urine even they burrow? Thank you so much guys!!