It's a bit difficult for me to advise, because it's decades ago I've used my set. I donated it actually to a friend. I've developed my own - no noise - method. The Morgan thing could be a good choice, but I have no experience with it. For instance, I don't know if it reacts the same as the conventional manometers. By that I mean the pace: indicating underpressure is one thing, but also the pace in which the underpressure changes (comes down after a blip) can provide useful information like a too lean setting. I don't know if the Morgan thing is doing this in the same way as conventional manometers. Others may know.
For those of you interested in where to initially set the adjuster screws of the oldstyle CB500/550 carbs, as a startingpoint for after they have been apart, I can share some advice. But, alert: these carbs do not need to be separated from the rack ever. Only when the O-rings at the T-joints would be shot, which is not likely to happen. Honda fit two on each side! Mine are still the originals (1976). One spring they leaked a bit, after hibernation prior to which I had drained the carbs dry for a change. Never did this before and I will not do it again. Luckily at that occasion those 8 O-rings have swollen back to their original size. Conclusion: if you leave your carbs in a natural state, which is wet and don't feed any aggressive fluids down the lines, they'll live forever.
