Pressurized crank case?

All engines will have some sort of blow by. The PCV helps but isnt enough on it's own to reduce the crankcase pressure to nothing. I would have it tuned as the rough running sounds more like a tuning and not-a-lot-of-miles type deal. On the overflow... The coolant will have to "find it's own level" again, as you drive it. So again, druive the car and dont sweat it.