I would ditch the lamp and put a towel over the top of the tank. This will help with the humidity but you will still have to spray the tank down at least once per day. Thats just the nature of the beast when using tanks. As far as them hanging in the cool side, it could be too hot on the warm side or they are just more comfortable over there. Make sure your temps are not to high on the warm side. Sounds like that might be a problem. A rack or tubs make a HUGE difference with the husbandry. Good luck!