Yes, although I've never used it, my understanding is vinylester resin is superior in every way but cost. It has superior properties of stiffness and heat tolerance. Vinylester gelcoat actually exists too but it is tough to find a place that sells it. I don't personally use vinylester because my composite supplier said most of the time it is overkill for automotive panels and I don't think people will want to pay a premium for it. If I thought people would pay for it, I would use it in a heartbeat.
I like that you are starting to use carbon fiber. It looks like you are just using a standard wet layup process. I suggest you look into vacuum infusion process. Your cloth to resin ratio will be better which will make your parts lighter, stronger and the surface quality of your parts will be higher. You will need a thinned down infusion resin and larger flanges to accommodate the vacuum bag seal. I plan to make carbon fiber body panels for my car and this is the route I am going.
I respect that you are looking to improve on Watson's parts because they were generally considered the highest quality you could get. I also respect that you want to keep an inventory. I agree with Tallon that it isn't unreasonable to build a part after it has been ordered but I prefer not to roll that way either. I am watching your progress with interest.
Mike