I also use crumpled newspaper with a larger hide. The BP's dive right in and push the paper over in front of the opening.
BTW if you're looking for an inexpensive alternative for the medium and large hides, Glad Ovenware 8"x8" and 9"x12" containers are pretty durable and work nicely for juvenile balls and boas. Five minutes with a pair of scissors and an emery board to smooth off any rough edges, and you've got hides. Amazon.com sells them in bulk with the free shipping option as well.