Had a handful of gift cards so I visited the numbskulls over at Home Depot.
I wired the Love controller into a heavy duty extension cord, breaking the hot wire on the normally closed side of the relay, as I've seen in some images on this site.
I put the probe in through the drain hole for the time being. Jammed a cotton ball in the hole to seal it up. Eventually I hope to make a more integrated setup; this was proof-of-concept more or less.
And here's the view inside. Two Better Bottles just barely cannot fit on the bottom. I'll have to build a collar before I can get a second carboy in there.
Once I finally realized I had to set d0 to Heat instead of Cool, it went from 75 to 60 in about 5 minutes.
So why are we setting it to Heat? Wouldn't it make just as much sense to set it to Cool and use the normally open side of the relay?