Just my two cents... Unless you purchase off-the-shelf RTR, or fully complete kits, you have to be ready to do a lot research and a lot of tinkering and improvisation. Helps to be a hands on kind of type. A one off cowling is really not that difficult to build, there are tutorials on line and so forth. I usually build my own, 1/16 ply for base, dense Styrofoam for body of cowl, two part epoxy resin and medium glass cloth. No expensive tools needed... Long blade box cutter a rasp and sand paper. Layer foam block to rough size of cowl, epoxy to ply and carve out desired shape. Sand smooth, glass whole thing and and the dig out the foam. It's a bit involved, but also personally rewarding to know you created a one off.
Keeping in mind that if you plan to race it competitively, to stick to class guidelines. Good luck with your builds.
Vince