Not in the garage but in the house. We had some new curtains and rails installed and I've been patching the holes from the previous rails. Some of the larger holes from the plugs are about 10c piece size. I stuffed them with rolled up paper towel then filled with filler, sand back, then final fill. Is it just me or is it 1 step forward 2 steps back with filler. I get it almost perfect then my OCD tries to get it perfect which buggers it and I have to start again. These particular holes are eye line when sitting on the couch so they have to be perfect otherwise it will annoy me.
What I use is,
Piece of ply strip, liquid nails, fill in piece of plaster,
Patching Plaster, a little warm water(helps it set quicker), let it set, sand.
It is tempting to play with it, Don't.
If I am in a real hurry, I will use a heat gun to speed up it setting.