id recommend using newspaper for substarte covered plenty of times but its just way easier to maintain keeps great humidity and is low cost... i just learned to use cave style hides or hides with a tiny opening rather than a halff log for the BP security.... u might want around a 40 gal for an adult or bigger..... but your set up sounds great!!!
Trust me, 40 gal is plenty, unless you've got Godzilla in there haha.