32 Qt tub will be fine for most adult males and juvenile snakes. However some of the larger females may be a little cramped in a 32qt tub and fair better in 41qt tubs. Aspen is a very commonly used substrate along with paper towels, cypress mulch, newspaper, craft paper.
Anything but pine or cedar as the fumes can be lethal to snakes.
~*Rich
1.0 100% Het Albino
1.3 Normal
1.0 Spider
0.1 Mojave
1.0 Pastel 100% Het Goldfinger
0.1 Pastel 66% Het Goldfinger
0.1 Pastel PH Goldfinger