Bob, You could always set up two dial test indicators on the front plate after tightening the bolts. One on the washer just outside of the dowel and one just outside of the bolt head. Set them both to zero and come back a couple of hours later and see how much they have moved in relation to each other. The one outside of the bolt should move more. I know I kept re-tightening the bolts on my TBM prop and after about the fourth time the hub cracked. The Vess don't seem to have that problem. Also keep in mind that these props are side loaded against the four bolts so over-tightening is not necessary. I just snug them up in a set sequence and then run back through the same sequence until they all remain snug. If your spinner back plate has particularly deep serations it will usually take a little longer to get a new prop set into them as they cut deeper.