Only buy Scotch brand masking tape from an auto paint suply shop.
The stuff that is sold in hardware stores doesn’t make a good edge and is so thin it tears when trying to trim it with a razor. If you are going to go to all the trouble of laying out a complex checker grid, use good tape that will work and leave a nice clean edge. You get what you pay for.
One idea you may want to try is to wrap the tape in a spiral and cut the squares so they are on the bias (diamonds).
ohhh, you know what would be cool? it wouldn’t be checkered though, it’ be squares. but still. just put horizontal strips of masking tape on the frame, about an inch apart from each other or however big you want the squares to be. then when you do that completely, put vertical strips of masking tape about an inch apart, so you have a whole bunch of squares. and actually ya know what, if you wanted checkers still, you could do that, then take the masking tape off and put more masking tape on how I just said, but in a slightly different way, so the squares are in different places. then it would be checkered!! wow I’m smart.
ooooh, that’s a good idea too…and combine it with mine, so in mine instead of putting horizontal and vertical, put them slanting to the right and to the left. that’d be sweeet.