Heater placement
Lots of good info here, just wanna add, there is no 'single' best way to heat a given space. Sometimes radiant heat works better, sometimes a warm air heater works best. It depends on some variables, but if your garage has very much air leakage, a radiant heater rules. Warm air rises; moves up and out of your heated space. Radiant heat is not affected like that. (In fact airplane hangars are heated with radiant heaters. You could put in a couple dozen hot air type heaters and they would not even come close to the same results.) But if you took the effort to seal up those leaks and add insulation, you would probably be happy going that route. Hey man, whatever gets you out to the garage to twist some wrenches! Winters coming...