You are going to see a bit as ALL motors have blowby to one degree or another. That is exactly why the PCV system was mandated by the feds. How much you have is the question? That will be answered with the gauge. Any thing else at this point is wasted speculation IMO.
FYI: either 5/16 or 3/8 tubing will fit the d/s opening. You may have to reduce to o/d slightly with a file or belt sander. for a loose slip fit. You can put a short piece in with a small amount of RTV, allow it to set up, hook up your gauge with a piece of vacuum tubing and do your test. if you're going to drive it, make sure the tube is long enough to put the gauge on the windshield on inside the car