Well then to start with I would only move one at a time, with two different hands. This should be easy enough once I learn lefty mouse moving.

Then after only moving one at a time, and only casting with one at a time, using separate hands, I should naturally get better and better at it... Eventually maybe I can move with one and cast with the other, or cast with both at the same time.

Then after awhile move with both. Really doesn't seem that hard to me.

I think it will take a lot of practice, but I bet it's like riding a bike, once you get it, you get it.