I use either news paper or kraft paper. I have 41 qt sterilite tubs and bought 12 inch wide kraft paper at grainger.com. I think it was 900ft roll or close maybe. It has been a while and I just cut it to length cause the width is perfect. News paper is great also...just use to sections open up and they fit great. As far as humidity, I just use a big water bowl and one hide. They shed perfectly, eat, and appear to be happy. Ok just found the product info for the kraft paper.
product # 6twr0 27.35ea
30lb brown kraft paper, 12 inch wide, 1200ft