Steve,
your shed seems to be doing well temp wise, yes it does seem our weather sometimes goes toward your area, little heads up it reached zero today for a high, pretty much the same tomorrow but then a warm up for rest of week into 20s slowly reaching 30s so this is pretty good for us here anyways. Course we are going to get more snow tuesday that might or might not come your way.
Curious about the temps in your shed when it gets below zero similar to us and hope you have the same results as you seem to have put a lot of work in what you have done!
Best Luck and Stay Warm
Martin