According to the info I have, 37*f is doable and won't freeze over given the size of the AC unit vs the size of the area being cooled.
Coolbot has a calculator for their product.. If understand correctly, the coolbot shuts down the entire AC unit while the coils recover, they also don't interfere with the original control board or wiring.
My approach isn't the same, I'll probably be adding a second temp controller between the compressor, this will shut the compressor off and leave the fan running. That is supposed to prevent the coils from freezing over.