Fuel flow
Without disputing anything else said, my personal experience has been that I only ever nipped up a motor after a couple of miles cruising at 60 mph. The fuel tap was almost completely blocked. In more normal riding you'll hear it popping on the over-run long before any damage is done. I think the concern about inadequate fuel flow stems from US sprint experience. Since a Vin will do something between 45 and 55 mpg in normal use, the equivalent of 90 to 110 mpg if it were a single, I think the desire for fuel taps like sea-****s is misplaced. Maybe if you spend much of your time thrashing full bore up Shap it's a concern, but not otherwise. My concerns, addressed by using gas taps, was that every other damned tap I used, leaked.