For mine I used coconut fiber over top of organic, perlite free potting soil. The coconut fiber doesn't get soupy when it is wet but still holds enough moisture to help with humidity and for the females to dig in if they are gravid.
I bought mine at a nursery in a 2 pound brick. You soak it in water and it expands to like 5 times it's compacted size. I believe mine was ground. It didn't look shredded. It shouldn't be too hard to find. I have also seen it in pet stores around here and I live in-the-middle-of-nowhere-Kentucky!