Something else to consider about an unbalanced prop is this: it is not going to cause constant vibration. It will only cause vibrations at a few certain RPM.

Have you ever had a car with a wheel that was out of balance? I have, several times. It always seemed that thw car would shake a little at a certain speed. Like it would start happening at 55 MPH and then stop at about 60.

So even if a prop were so badly out of balance that it DID cause vibrations, the chances that it would vibrate in a speed range that you are using is slim.