The UTH should be plugged into a thermostat, this is not an option, it's a must.
With a thermostat you will be able to set your "ground temp" to 90-92 and then add your secondary heat source for getting your ambient temperature correct.
I didn't read much of the thread...but you keep your blood'd enclosures at 90-92F? From what I've gathered (from many a breeder), a hot spot of 86F is enough with an ambient of 80-82F.