Most of the issues seem to cone from the xr flo torq kit.What I have found is that there is a variance on the hubs,and on the square bore of the props.These two combined can still pass specs but you end up with what your talking about.Simple thing to check would be that the rounded edge of the black strips are at the bottom of the hub,(gearcase side) this can cause that.I had a customer that wanted to crucify me last year cause his triple set of five blades he was trying out 4th of July weekend,did not want to fit tight(hubs) so he did not run the boat.When I got the props back we took every measurement known to man and the props were in spec,so I grabbed about 30 hubs and found three that fit so good you had to pound the last half inch down with a rubber mallet.Word I got from my hub distributor was that they have a new supplier(I get em from a Quicksilver Dist.) so that could be an issue.Solution and it works wrap the S.O.B. with some Duct Tape till you have to pound it in the rest of the way and you are on the water.Once it is tight in there it cant move because of the four flat system.Even if it is loose you might be able to notice it at an idle,but once there is a torque load on that hub it cant go anywhere,obviously this only applies to the metal xr hub kits.Hope this helps.
TBuck