you did it right.
I wish I had done the pex for radiant heat for my 40 X 60 shop on the working end. I have big woodstove and I was using the backhoe bucket or 2 load of firewood each day. And it would just thaw you out a little bit. I was spending the winters working in sunny Calif and forgot what 40 below was like up here. I don't know if it is efficient enough but some people have used solar heat on the cloudy Oregon coast to heat water to 70 degrees then a heat exchanger to bring the floor loop temp higher.