Yes Rich that is enough vacuum 'if the system is tight'. A vacuum system must be absolutely tight with no leakage what so ever.
When you say you "rebuilt" your wiper motor do you mean that you cleaned it up and reassembled it? Because as far as I know there are no new parts for them and there hasn't been for a decade or more. Simply cleaning up the motor is no guarantee that it's going to work. The weak link in the motor is the paddle/piston or what ever you choose to call it. It must be "VACUUM TIGHT" for it to have the power that it needs to pull the wipers.
The only way I know to get a good rebuild on a vacuum motor is to send it off to The Wiperman who has a monopoly on new parts and can give it a real rebuild not just a cleaning.
Denny Graham
Sandwich, IL
