Thanks for the information guys!
I was unaware that PAM was just for porous surfaces... When I sprayed the tub, I sprayed the sides and the paper towel / newspaper substrate. After it dried, I moved it into the area it would be at for quarantine, but managed to spill some of the water from the water bowl, thus had to change out all the substrate, so I guess it was a useless treatment.

If I see any signs of mites, I'll retreat and go from there and I will spray the carpet / area around the tub.

My new snake looks very healthy and shows no signs of mites, so I have my fingers crossed that I won't need to worry about it.