Re: shop heating
We have had excellent luck (and cost savings over forced air) with Infrared tube heaters.
It warms objects not the air, once the floor and everything else is warm it doesn't take much to keep the place warm.
You will notice that you can open doors and run equipment in and out without loosing the heat that is already in the objects in the room. This translates into faster recovery of shop temps.
IMHO you can't go wrong with tube heaters.