How does High-RPM performance feel? Interesting idea, that's for sure. I'd need to see some dyno curves to see if it's really worth it though. At least it's an easy experiment.
Which method did you try? Connecting all four carbs, or 1 to 4 and 2 to 3?It appears the FZ1 must get its vacuum signal for the petcock somewhere else as they don't mention a tee for supplying a vacuum signal to the petcock.