I inherited this trait from my fathers side. It was there from birth but then, due to neglect (temporary monastic lifestyle) it went away. Then after a few months of just fumbling around in my late teens I re-developed my genetic blessing. Nothing much to share really. Most peeps zoom with a primary hand, I have this uncanny ability of not loosing a stroke by using one then the other. Zooming is real fun. I have never used both at the same time, I may put that on my "bucket list". Life is short, enjoy as many moments as one can. So I do. 8)