[Varn]

Might say that my 700 virago runs a single 34 mm standard Mikuni VM carb. I don't make any attempt to get extraordinary mileage like you do. I get around 50 mpg. The carb sticks out the left side of the bike. More than once I have adjusted the idle speed or mixture while stopped at a sign. Just reached down and turned the appropriate knob.

At any rate the VM carb has a simple slide throttle. Mine will run 75 or 80 mph with the throttle open 25% giving me a throttle opening of 34x8 mm. In other words I probably could run that fast with a 17 mm slide carb. If you choose to do something similar make your intake runners fairly long and choose nothing bigger than 21 mm carb or carbs. That way you could hold it open nearly all the way and you could be on your main jets. I would also make sure that there are steps on intake side from small at the carb to bigger at the intake ports to prevent reversion.

One reason the Mikuni VM is still pretty popular after nearly 50 years is that it has a full range of jetting. Just look at the Sudco online catalog.

Had to snicker when I read that you were going to consult with an engineer about what to do with your carburation. Most engineers that I know I wouldn't ask about such mundane things as tuning. They wouldn't have a clue. You probably can tell that by the way that I write I am not an engineer.