Brackshooter,
When you say "waving in flight" do you mean up and down or left to right?
One thing I guess I gotta ask is, if you are getting good groups out to the distances you want to hunt, what difference does it make if the arrow does summersaults before it gets there?
I realize that is stretching it a bit, but way back when, when I started shooting a longbow after a lifetime of recurves(up untill that point in my life anyway), I also thought the arrows were doing funky things. That is until I learned a little more about the whole archers paradox thing.
In my experience, recurves are a little less picky about spine and shoot well with arrows spined higher than would be recomended. This would mean arrows come off a cut-to, or cut-past center recurve with less paradox than off a not-quite-cut-to-center longbow (which would be pickier about spine). Stand behind a selfbow shooter and watch their arrows go through paradox and ya wonder how they can ever hit anything, but they do.
I shoot extreemly stiff arrows out of my recurves, and have to dial the spine back (or the point weight up) for my longbows. Since there is a lot less wood in a longbow riser (usually anyway) I believe you see more of the arrows initial stages of flight. Pair this with more movement during the paradox recovery portion of flight and I think you have what you are experiencing.
As long as you hit what your aiming at, and the arrow is straight into the target from where you are shooting, your fine.
Hope this helps some.
OkKeith