But to me "ultimate" implies can't be topped, or at least better than older designs. I'm not trying too be argumentative, just wanting to see whats to be done.
Mayhaps I can contribute as well, having designed a few things.
First off, I'd suggest an agreed upon set of objectives for the project gun should be established and listed prior to drawing it up. It seems so basic, but such a list of objectives can help everyone stay on track and avoid early compromise.