Prop rebuild update:
Having old school engineers that like to monkey around as friends is a real blessing. Prop is now rebuilt and looking better than new for about $200 and a good bottle of scotch which includes in-water re and re.
Further investigation found that the blades were indeed off centre from the shaft. The hub has now been balanced, and the pin bored to 1/2" allowing it to be centred. The blades, probably due to pitting, were mismatched mass by 28 grams which has now been corrected and balanced together.
The test drive comes tomorrow after we put it back on, hopefully without dropping any parts!