Have used only NPV for gluing feathers to aluminum ever since they came out with it, which was about the same time FletchTite changed their formula so it didn't work very well on aluminum anymore. Never prep anything, shaft or feather. I just put glue on the quill, and let it set for 20 minutes in the clamp. Never had a feather fall off.
I'm not saying that NPV is necessarily the solution to your problem, it was just the solution to mine. Other people on this forum have written that it doesn't work for them very well, or at all in one case I remember. I don't understand it; there is a lot of speculation as to why it works fine for some people and not for others.