Pattern progress:
First, thanks for everyone's suggestions. I agree that dowels would have improved things a lot, and even brad nails have their place. so, maybe next time... In the end, what I ended up with was not as bad as I feared. I tweaked the bottom surface to make it more square to the new (skewed) sides, then took out the rest with judicious hand planing. In the end, I had enough fat in my rough cut out to fix it without having to add any material.
As you can imagine there was a lot of time spent squaring up and flattening the subsections. Then I glued up the RH wing. After that cured, I spent even more time cleaning up each wing, since the alignment of each of the five pieces that make up each wing is not perfect. I mainly used hand planes for leveling the surfaces, but some hand sanding and even a belt sander were also used.
I was not real happy with the fit of the joint between the wings and the middle section. To improve that, I put waxed paper on the joint surfaces of the middle section, buttered up the mating surfaces of the wings with thickened epoxy and squashed them together. A few clamps to hold them over night, and after some clean up today, they mate really nicely. Recall that these wings remain separate pieces, so that they can be removed from the sand mold before the middle section.
The latest picture shows all pieces together. The dark spots are areas that have epoxy fill to take care of low spots, voids in the plywood and self induced errors (did I mention that belt sanders can do damage really quickly?). I have 62 hours in this to date.
The remaining tasks are: additional fill, smoothing, edge rounding, filleting and finishing. I will also be starting on the follow board.