I must be unconventional!
I'm RH and have to wind a spinner with my RH, I'm too uncoordinated to do it LH. Butterfly jigging is very dependant on the winding hand syncronising well with the rod hand. Since my RH is the most coordinated, I will always use it.
I also don't buy into the argument of using your strongest arm (RH) to hold/control the rod. The rod hand is usually outstretched when the weight comes on and only needs to pump the rod within the drag setting of the reel. This doesn't need high strenght.
I almost never use a spinner anyways.
