They are burrowers so crumpling extra sheets of newspaper will work fine. I have a female just over 4ft and around 12lbs. I ordered some large cages but her temp home is a 42x18x7 tub. I have to say it's a bit small. I have the warm side with a thick layer of mulch she burrows into and just crumpled newspaper on the cool side. IMO adults should be in a cage not a tub. I have read all different suggestions on what the humidity should be and keep mine between 55 and 65 and have not had any issues as of yet.
She is by far the sweetest snake I own. She is hissy when you first touch her but she never does any more than that. As soon as she is out she is a complete sweetheart. She will hang out with me as long as I let her. The only problem is she can get heavy around the neck after a while.
I have absolutely fallen in love with bloods by getting her and will have many more soon. I Love their heavy build and colorings.
They do take up a good amount of space as adults and when they go to the bathroom you will swear a baby elephant stopped by, no kidding.