just to add to the thought, having an unbalanced winding will also likely cause quite a bit of vibration, as well as the other problems Flux mentioned. i could be wrong, but don't think so.

a possible solution. connect your genny in delta and leave it there. pick a cut in speed which would suit the delta mode.

we have discussed quite a few times this concept on the irc chat.
one of our members there is "ibedonc" who builds a lovely voltage booster.

it basically takes your lower than cut in voltage and raises it so that you charge your battery. when the rpm becomes great enough in the genny to charge on its own, it electronically switches over to direct from genny. the voltage booster can be adjusted for whatever parameter you wish to keep it operating.

this would give you all the benefit of low wind speed charging plus the higher output of the delta connection.

join us sometime on the irc chat. everyone is welcome.