Actually belly heat isn't that important really. Ambient temps are more important. I don't use UTHs as I don't trust them even with a t-stat. I strictly use RHPs in PVC cages or CHEs on tanks, obviously both with Herpstats as I'm a Herpstat guy But you can use both, just have to make sure you have both set up T-stats. One to measure the UTH and another to measure the ambient temp on cool side. And like mentioned, if you slide the water dish close to the CHE, it will help the humidity. Same trick works for RHPs too as they both function on the same principle except RHPs wont instantly melt flesh if touched unlike CHEs.