I'd got the impression you were spraying the mask on and then cutting it away with a scalpel. I thought it might be easier to get clean lines by painting the mask on with a brush.
I don’t think I could get clean lines and have it thick enough if brush applied. I suspect the pros are either freakishly good with a scalpel or they use stencil masks printed on a plotter.
Yes! This is that kinda stuff. See ^^^