Yes, you should have one hide on each side, and yes, it's fine for it to be over the UTH -- as long as you know the ACTUAL temperature there, which you don't if you are using temperature strips or analog thermometers. Otherwise, you could end up with a snake with a burned belly. If you read through old threads here, you'll see that people have discovered their analog or strip thermometers were wrong by as much as 20 degrees, which is a tremendous difference. The strips are no more accurate than trying to guess the temp yourself by feeling it with your hand, frankly. I'm not trying to be harsh, I just want to be clear that there is really no benefit to sticking a temp strip in the cage as it is no help in judging whether the temps are appropriate. Maybe a neighbor or friend has a thermometer that she or he would let you borrow so you can check your temps until you have room in your budget for one.