Wow, nice to see some hand painting!
Re the checkers, I had an idea a while ago for a checker tail mustang scheme: Paint the entire area in the lightest colour. Mask completely, measure and carefully scribed lines of checkers with craftknife and flexible ruler (or similar), remove squares (or diamonds depending on angle) requiring darker colour, and if all succeeds, a nice checker-pattern of masking tape should remain, ready for the darker colour... worth a try!
Btw, nice save too, and got some spare canopies if you need one.