Using a random-orbital sander, I sanded both plates with a 360-grit sandpaper. As you'll see in the picture, the yellow stain removed very evenly. I followed up with a wood block to ensure that I didn't introduce new irregularities. The stain still came off very evenly. Apparently my shaping of the plates was quite consistent.
Apart from the purfling grooves and edge dimensioning, the outsides of the plates are pretty much done. Using a standard F-hole template, I laid out the F-holes and drilled the end holes. Now I can lay out the inner drilling guides and drill the depth guide holes.