my propane heater had my garage up to 80F+ for quite a while over the weekend. Still just rocking the Mr. Heater convection heater...
I can remember working on my car in the driveway in winter before….a heater indoors is a luxury comparatively!
throw a small fan behind the Mr. heater to circulate the heat and it’ll be tshirt comfortable!

That is what I use for heat, on a bigger scale. I have 700 gallons which might last this winter.im still over here burning old motor oil for heatView attachment 431403
i can remember some cold days being convinced it was warm enough in your shop or mine in edmonton, once the heater had been going for awhile.. but its only the top 4 ft that are warm, anything on a bench or dare to lay on the ground and its winter all over again haha. I remember learning to wrench on my first car, a 1990 ford exploder in edmonton, pick n pulls all winter long, driveway wrenching in the snow.. was horrible but makes you appreciate what ya got done way more.... 240v heat sources are nice though haha!
I was going to mention the ceiling fan as well but to answer your concerns, it doesn't have to be in a specific place to work, find a place out of harms way, it will still circulate the air and push some of the heat down and eventually it's all warm.I'd worry about getting something into the fan itself, I only have an 8 foot ceiling.
It's all good, I'm indoors and have a heater. Until we moved here I did everything in an open carport...