I have a 72" x 22" x 12" pvc cage currently being heated by a radiant heat panel and housing my boa. The hot side floor is 86 - 89 and the ambient temperature is 80, humidity sits around 50% without misting or moss.
The cool side of the tank sits around 72 on the floor and the ambient is similar.

72 seems a little low, if I should do something to raise the temperature, I have the option to add either heat tape or a RHP easily but would like to know which is better before making holes in the pvc.

I find RHP's dry the tank more, meaning a second one would likely drop the humidity below 50% so is ambient temperature or belly heat more important?