What temp to set my t-stat on

[bcr229]

I usually have to set my t-stats at 92-94 to get a surface temperature of 86-88.

OP has a rheostat not a thermostat. OP needs to bear in mind that if the ambient room temp increases or decreases throughout the day, which is fairly common in the spring and fall if you aren't running the HVAC, the temperature of the pad will rise and fall also.