Bum, I've probably built 25/35 combat planes in the past two years, all with v tails. I've found the tail wag in a lot of them, and used to fret about it. But, then I discovered it was not affecting their handling (turn and burn, yank and bank) so I quit frettting about it. The v tail is just a natural on the bat.

I have heard, but have not researched it, that the full scale Bonanza with a V tail has a little of this same tail wag.