Just a little update,
haven't forgotten about this project, just haven't had much time for it.
Oh, and Block sanding SUCKS!
That jig worked out really well.
here's a pic after the first 2 or 3 layers of plaster.
one of the first almost full passes, but still rough.
and after a week or so and a bunch more pulls it starts to take shape for real:
One thing I didn't even think about was how damn long it takes for plaster to cure/cry out. you can't add plaster on top of still damp plaster, so the plaster layers were added days apart
now it's time to fill the lower corners or 'cups' of the fender. Same foam trick as for under the plaster pull.
glued in place and glassed over the foam edges.