I don't think that makes you a gear head, 2nd Tenor - unless both of us are! I don't constantly chop and change from one mouthpiece to another, and I doubt that there is a 'perfect' mouthpiece - but I am pretty certain that the essental thing is that mouthpiece, instrument and player match each other.
When I had my Regent baritone, the Besson 7 mouthpiece suited it and me nicely, but when I passed the Regent on to my band and got the Packer baritone, with a slightly larger bore, the Besson 7 made it feel a bit choked, and the Wick 6BS was a better match, and much easier to reach the higher dynamics.
A long time ago, I read a book about motorcycle engineering, written by Phil Irving, who designed the Vincent 1000cc V-twins, and he stressed the importance of what he called 'proportional tuning'. His approach was to ensure that an appropriate state of tune was chosen for the bike, depending on the use to which it would be put - roadster, scrambler, trials bike, sprinter or speedway bike - and then all components and dimensions, such as carb size, jets, valve size, cam profile, compression ration, and exhaust, were chosen to match that purpose and the required state of tune.
As he said, there's no point in fitting a huge carb to a bike if the valve size and cam profile don't allow for a large and fast enough airflow to take advantage of it, nor is it appropriate for a roadster meant for use in heavy traffic, as the pulling power at low revs will be very poor. In such a case, the bike will perform far better, and give much better fuel economy, with a smaller carb. Equally, he said, there's no point in fitting large valves, high-lift cams, and a high compression piston, but using a small bore carb which will strangle the gas flow.
So there is no 'best' carburettor - and I think no 'best' mouthpiece; it's a question of making the whole system match, from your lungs to the end of the bell. At least, that's in my unhumble opinion! (I had my humble opinions surgically removed, years ago . . . )
With best regards,
Jack E