I was just going to post an update today.
I've been busy working on the cowling lately and it took some time, but with some help from a good friend everything went well. First i had to finish the CAD model of the cowling by adding the lateral air intakes and making sure their shape will help extraction from the mold. The mold plug plywood structure was filled with depron blocks, sanded to shape and glassed. The next step was adding the lateral air intakes and smooth the edges with automotive body filler. Everything was finally sprayed with gelcoat and sanded again. The mold construction is classic, so i won't go into details.
I attached a few pictures showing the main steps for the mold plug, the finished mold and the final part as extracted from the mold.