Not to diss you Rich but sometimes I feel many are quick to jump to certain conclusions and find someone to blame. I dont think his temps are all over i think he was just referring to his temp gradient.. I dont think his temps would really be 80/82/85/88. If its a 20g tall the floor space is about that of a smaller one, its a little big but i think it shouldn't be horrible if you just clutter it a little more if it isnt already. Yes pinky mice aren't the best food source but he has his reason. You could suggest increasing it to a hopper or subadult but don't jump on him over it so fast. Just let him know.
So, back to responding to the post, as many have said, slightly large cage, and as I have said, fill it up. Best thing you could do for now if you can't get a smaller one. Black out the sides and back if you have not already done so, helps with security. Night time temp drops are not necessary, I know many care sheets have said so but really is not. If it happens, so be it, but it does not need to be deliberate. Some breeders do it, some dont, both successfully.