I would not waste time with this. It might work, but that lower temp limit isn't going to satisfy you for very long.
You can find the Johnson Controls A19 analog temp controller on ebay for less than $30. Make sure you verify it has the correct temp range (some are not appropriate range).
If you buy off ebay, you will likely need to take short 3-prong extension cord and do a bit of wiring yourself.
Or, pay Northern Brewer $60 for the correct controller ready-to-go.