I have no experience with a one vac. gauge set up, but I don't see why it shouldn't work. If differences in vac are not that far apart, it is a sensible and economic way imo. If differences are widely apart, it could be a bit difficult however.
Having said that, please note that readjusting the vacuum is rarely required (see below what Honda states in the Owner's Manual). First do all the other sceduled maintenance - in particular the ignition - and I bet most of you will have a nice running engine again.