The top plate didn't fit very well in the plaster mold for the bottom, so I had to make another. It's not that modelling plaster is expensive, but it does seem a bit of a waste. I was able to remove the first mold from the frame intact, so I hope to be able to use it in future. In any case, I mixed a bit too much, and too stiff. I was barely able to press the plate into the plaster to the point where it would be held in place. I had to apply temporary clamps to the ends to hold the plate in place for planing.
I did the rough removal with Lee Valley's Veritas Pullshave. This did a very fast and controllable job on the spruce. The large and medium finger planes then made quick work of the final shaping, then the scrapers took everything down to a smooth finish. As with the back, I got quite close to desired thicknesses, with just a few areas needing touch-up.