Hey bjuice, kinda new here and always enjoy reading your posts...along with many others.....cool site.....
anyway
I will start with the short answer, If your motor is happy, and the vaccum pump isn't injesting a bunch of oil I wouldn't worry about it. As far as a specific number well first I would need to ask where are you pulling the vaccum from ie valve cover, intake valley, block? and are you using nitrous or anything else that would have you running a ring package that would require high vaccum numbers.
One other thought...If you don't have some kind of data recorder or a gage with a telltale do you know how much real world vaccum you are pulling?