I finally finished carving the foam plugs for the side panels on the bike, and started laying up some fiberglass parts for the 750. The resin is still curing, so I don't yet know how they turned out, but I'll edit this post in a couple of hours to show the finished product.
...which brings me to one of the cool things about working with foam and fiberglass: if you screw something up, it's not the end of the world. Carve and/or sand out the botched area, then rework it until you are happy. If you mess up a piece of foam, you can glue a new piece of foam in place, then carve or sand it until you are happy with the shape. If the problem is in a piece of fiberglass, use a saw, knife, file or sandpaper to carve out the problem area, then lay up a fiberglass patch over the area. When the resin has cured, sand the patch smooth and voila! Problem solved :)
Edit: As promised, the photos of the finished layups:
Here are the side panels fitted to the bike after some preliminary trimming: