[6sunset6]

I swear by radient heat. If you super insulate and vapor barrier to control drafts I will bet you can heat the building for free. Solar hot water panels on the roof, solar electric panels for pump power. Use antifreeze in the system , better the potable kind incase it ever is in contact with domestic water. A shop at 45d is plenty warm enough. A very small wood stove would boost it the rest of the way if you need it. I have radient heat in my house that I heat with propane. My shop was built 7 years before my house. My house was built 16 years ago. I kick myself everytime I think about it.
Or a ground source heat pump. They were still to new when I did all my work but they are readily available now.