In your case I would recommend a Modine ceiling mounted heater, either nat gas or propane. I have one in the back part of my shop, which is 40'x40' with 10' ceilings. It draws combustion air from outside and not inside, which is good. It serves the purpose for that part of my shop.
The front part of my shop is 46'x48" with 14' ceilings. For that part of my shop I installed in-floor radiant heat, which I absolutely love. Heat comes from the floor and works its way up. My feet are never cold. It was tricky because I installed a 13' BendPak lift and I had to be sure ahead of time that I knew exactly where the PEX tubing was, so I didn't hit a tube. Worked out perfect for our cold Buffalo, NY winters.
My in-floor heat system with Navien condensing boiler.
Before I installed my lift.
After installation of my BendPak lift.
