Thats pretty cool to see you fixed your problems. I'm still a little uncertain as to how it works, but nonetheless it does work, so thats great!
Do you think resonance wouldn't be an issue had you used the 269 oz/in motors from xylotex?
Are you happy with the 425 on the z-axis? I suppose one of my decisions will be to see if a 269 oz/in compared to the 425 oz/in would work better upon the z-axis.
What I'm getting at is perhaps the resonance is a function of the 425's?