In refinishing a huge quartersawn oak and ply bookcase for the local library (gratis, but fun none the less) I came up with one plywood side slightly lighter and yellower than the rest of the cabinet. In order to get even stain, I had given a shellac wash to the cabinet, which made addtional stain difficult.
A quick coat of Polyshades (polyurethane finish with some colorant added in) on just the lighter side did the trick nicely; easy to control the additional color, and a first coat of finish to boot. I had never tried this before (not a good finisher yet) but it has earned a place in the bag of tricks. And you see any runs that will develop immediately -- you would have to be blind to miss them
Matthew