We found the thermocouple on the supply air near the heater was not reading properly (too low). I replaced it with a more robust model and now it reads as we would expect - highest temperature out of the four we're monitoring; temperature gets cooler further from heater (vs opposite we were seeing yesterday). TC#2 is now near the REGEN pipe near top of enclosure, reading air temp. TC#3 is on metal valve on bottom of CP4, reading metal temp. TC#4 is clamped to GV11 lifteye, reading metal temp. We are heating again at 1C/hr and will monitor closely.

Kyle installed a flow restrictor plate on the return duct which covers ~80% of the 20" diameter as a quick way to reduce flow. We could also install a GV VFD on the fan motor which has same specs at GV motor.

Mark D. and Mark L. (and Bubba from home) came to the rescue with some ducting parts that we can install inside the enclosure to extend the return, if needed. We will continue to bake as-is and see how the temperature profile changes with time.