If my corns aren't in blue or in a food coma they are normally pretty active depending on the time of day. If you walk into my snake room during the day most of them will pop their little heads out of their hides so see what you are doing.
I've heard a good rule to follow is 1.5 times the size of the corns head.
Most of the corns I have or take care of are fine with mice, though one of them is a big boy and he is on weaned rats.
Prognathodon - I like that tower you have. How are the pieces connected at the top?