Plasterers use a technique like this when installing plaster trim moldings around curved openings. I understand that the the layup is flat to make gravity work for you, but what about wiping it up on edge around a mockup of the cockpit opening? Make it in final shape so you don't have to bend it at all. The plaster guys expect to hit it 3 or 4 times to get it right. The first shot just builds a base, with lots of gaps and low spots, and they go back on it (with no additional material) until it gels. The subsequent coats are much thinner, and less prone to sagging. Seems to me that some combination of colorants, Cabosil, microfibers and microballoons would provide thixotropy, optimum weight, smooth finish and matching color.

: I think this might be a better idea than Bondo. Mixing up a thickend epoxy
: should give you something more durable and compatible. If you can get
: microballoons you'll have a lightweight filler material. Otherwise, try
: mixing a sample of epoxy with finely chopped foamed styrene (the
: insulating boards sold under the name of Styrofoam would be suitable, as
: would similar products) How you would turn this stuff into a fine powder
: may be a problem, but one you should be able to solve. One ides: feed the
: edge of a sheet of foamed plastic against a belt sander loaded with coarse
: grit sanding belt.

: Add some glass cloth threads to the mix for strength and to resist cracking.
: Cut a strip of glass cloth an inch wide and pull out the long pieces so
: you get a pile of 1 inch pieces of glass fibers.

: You want a material that is mostly light weight filler and that is held
: together with a minimum of resin. When you get the shape right, cover the
: thing with layers of glss cloth and resin for added strength.

: PGJ