I personally would not use only heat tape for a BP unless the air temps in the room are kept like 78+. My BC is in a boaphiles cage with only heat tape, but the BP's need the higher ambient temps. However the thickness of the PVC doesn't affect the UTH, those can get pretty hot!
Dont mean to change the topic but since you brought it up, what are the differences in ambient temp requirements for a BP and BOA. I’m going to put a Boa in my old pvc cage which has two UTHs and no RHPs.