Regarding vacuum leaks i want to forward my expirience. When i was blowing and sucking for testing purpose through the tube that usually goes into the air inlet tube, i've noticed a hissing sound from the oil filler tube cap. This oil filler tube cap was "my" vaccum leak. By turning the cap with force into one or two full revolutions the cap and the vaccum becomes tight and close as it should.
Another leak i've suspected where the PCV is plugged into the rubber. The PCV was sitting loose there, much to easy to unplug. With some heat resistant tape around the PCV the connection is tight now.
That is, i belive, the way i've fixed the vaccum leak in different ways. As a side-effect, no engine-oil is dripping down anymore onto the starter motor..

DIY or die - btw: i'm trying to extract a faulty dent out of my mouth at the moment