First you have to forget all of the BS that is fed trumpet players about what makes a mouthpiece work. A bigger backbore or throat does not necessarily make a mouthpiece/horn combination more free blowing or darker. It can really mess up the intonation and high range playability though! Check this link out:
Welcome at the pages of the IWK (Institute of Musical Acoustics) then click on research, then mouthpiece forms. THAT is what happens when you change parameters. It would slow down many mouthpiece safaris if the players checked out the real poop first!
Freer blowing is very often something that involves your body and not the hardware. The ZeusF2 is not a "standard" mouthpiece. Do you have a friend with a Bach 1 1/4C or 3C. Try and find one play it and post again with your results. Maybe we need to give you some breathing and not mouthpiece advice!