Two things you might want to think about. I would be hesitant to put up hardboard on the ceiling, my father did the same thing when I was a kid and after a few years ti was sagging between every joist. I think the hot humid summers did it in, maybe strapping 12"OC would eliminate the problem. Your need to careful with your heat source, it dumps a lot of moisture into the room, if all your tools are cold they will get condensation on them and possibly start to rust. Maybe you can just manage it by limiting the run time of the heater.
I have a quick and dirty gear room ceiling made from thin lauan paneling. I screwed that in along the ceiling joists, and covered the seams with thin wood strips. That has been up for 15 years with no sag, although that room is kept dehumidified year round at 50 percent max. With the dehumidifier off it will hit 80 percent at times.
I had never thought about that hardboard and moisture. Using that stuff on walls I would be afraid I might accidentally bust hole in it.
I had not thought about moisture from the heat source either. Is that worse with gas than with electric, or is it just the sudden rise in temperature? Maybe slowly warm and cool off the shop space, or run a small dehumidifier. The latter could be advantageous for humidity control when doing paint or varnish work. For that purpose likewise a small AC unit in summer.
One thing about whiteboard, or sheetrock, or just white walls or any kind, it is a lot brighter with white surfaces reflecting light around the room. A dark walled room is not as bright. The lauan ceiling paneled gear room is awfully dark no matter what. It does not help that the white painted cinderblock walls in that room are 90 percent covered with stuff, and the dark grey carpet is not doing the illumination any favors either.
I painted all of the tool hanger pegboard in the shop white for that reason. The pegboard surrounds my main workbench on three sides, right where I want the best light. The white helps. Whatever you use for walls and ceiling, I would paint it white. Or a very light pink. I will send you some swatchs.
And before you start hanging shelving or pegboard or lights, pencil mark the length of each stud or ceiling joist on the walls for future easy find reference.
