I installed my STC-1000 in the bottom louvers on my TRUE GDM-10 Fermentation Chamber
. The existing thermostat is bypassed. Existing wires were used between the lower and upper enclosures. I ran the probe wire through the existing wiring hole in the floor of the unit. The Heat 1/2 duplex receptacle (and an always Hot other 1/2, not on schematic) were installed in the original thermostat cut-out, in case I needed to control a smaller heater or use some other AC device inside the chamber.
IMO, bypassing the thermostat is a better option in that it allows the evaporator fan to run constantly, which promotes defrosting and air circulation.
The heat strip turned out to be oversized and I haven't actually needed to use it all winter.