So I reached out to Dion at Spyder Robotics LLC (Herpstat) about my issues with spikes in temperature when a shelf is involved. He agreed that with the probe below the shelf, you are gaining too much heat above it and when it finally gets up to temp it turns the power off but the heat build up above keeps providing heat and overshoots. Then when it cools down its taking too long for the heat to build up again so you get a big drop in temp before it recovers and is why you get the big swings in temp.

He recommended putting the probe "directly" on the RHP which I haven't considered because I've never heard of anyone on this forum recommend such. Also recommended securing with tape which I know enough not to go that route.

Currently, I have the probe dangling an inch from the ceiling in the corner of the enclosure. I've seen more consistent temps this way but have also witnessed some spikes (i.e. 88-90 most of the readings and then an occasional 90-92 reading).

Any ideas?