'easy' vacuum question

I am trying to get my ignition map as close to the needed values as possible, but I know there must be a lot of places that the map isnt really used after you put a turbo on, so I probably shouldnt waste my time trying to mess with the entire map. What I was wanting to know was how much vacuum/boost there is when you're cruising down the highway (~2800 rpm), and when your just at an idle, (~800 rpm) when you have a small turbo.
I know that theres no way for me to get an exact awnser, but I just kinda wanted an idea of where to start. And for referance, im basically at sea level, about 2000ft I guess.

Thanks,
Buzz1167
Jon N