107 people beat me to this thread??? Unfreakin'believeable....
In answer to your questions, no the smaller size NPT fitting won't matter as long as you have no air leaks around it.
As far as the hose, heater hose as a temp fix is OK. The circuit there carries hot, oily fumes so heater hose will break down pretty quickly. PCV hose is what you need for the long run.
Oh...and next time, go a little easier on the parts!!! LOL