I use blue OR pink foam (what ever I have on hand). Blue sands easier than pink.

After the plug is carved/sanded to shape, cover it with a LOW TEMP film (stops the resin from eating the foam). I then wax the plug. Depending on the plug shape, you may be able to save it for a second cowl.

For a 40 - 60 size I NORMALLY use 3 layers of 4oz cloth. I use finish resin.

I apply the cloth/resin as follows: LIGHTLY spray the cloth with 3M #77 adhesive. Then cut the strips of cloth and apply to the plug. I then mix the resin (about 30 - 45 minute work time) AND CUT IT about 25% with acetone (makes it VERY thin). This thin mixture I work into the cloth with a "flux" brush until the film color is clearly seen. Let dry (about 48 hrs). Then rough sand and apply a coat of regular mix resin and let dry.

Make sure any excess resin and cloth are clear of the bottom and cut a 3/4" - 1" hole in the top center of the glass. If you have done everything "right", the plug should pop out and be reuseable. If not, make an X slit in the back and pour about 2 - 4 oz of gasoline onto the foam. Come back in an hour and pull the film and "sludge" out.

The cowl is going to be VERY flexable at this point. Do any final shaping and let dry for an additional 72 hours. THEN you can sand and fill as needed (I use the red spot putty for filling any low spots).

I use automotive type sandable primer to prime the cowl and paint with your choice of color/paint. If the paint is fuel proof, clear coat it with a THIN coat of "Crystal Clear" Lustercote.

Hope this is what you wanted.