[jambo]

This will probably work, but it involves you going back and forward between carbs, each time you will probably over compensate and have to adjust. It's nicer to be able to see both carbs working at the same time with a conventional set of vacuum gauges. Also if it doesn't seal properly when it's put over the throat of the carb you'll get a different reading, and it changes the air resistance that that carb is working with by blocking it off.

I'd put my cash on a normal set.