I got to tell ya guys, I don't ever prep a shaft unless it is Carbon Express (they have a lot of release agent left on the shafts from mfg).
I don't have any problems and we do thousands of inserts a year. I did have one or maybe two guys mention that an insert came out, but can only figure It was our mistake and not the glue.
And no, not all hot melts are created equal. I have tested others that didn't hold up, but i'm sure there must be a few that work well too.
Thing is, one $7 dollor slug of it will do maybe 30-50 doz inserts. It depends on how much you waste. We ussually just throw away the excess that rolls up at the end of the shaft and still do at least 30 plus dz with a slug.
thanks,bigjim