IM not sure if this will help, but it worked for me and I have a 60 gallon tank for my male BP. As I dont use any over head lights and have only the UTH to heat the tank I simpley got a large water dish and placed it so that half the bowl was on the UTH. Made my humidity jump from 40% if I was lucky to 65% over night. And when the shed was starting I will mist and the humidity climbs to 82% and holds there until the shed is done. I then leave the top open for a bit after he sheds and allow some of the humidity to escape and return to normal. I only open the tank when I can completely supervise the snake so I dont end up with a missing BP.

I hope it helps you,

Regards,
Beauty the BP