buy mth -
www.multitablehelper.com - it lets you use your keyboard to play.
if you're brave, you can also opt for voice command, but i am nervous about the reliability of it (i've never tried it)
the amount of effort you save from not moving your mouse all over the place is huge.
you save time, you reduce effort, you reduce misclicks, and you reduce wrist strain. when you stop worrying about the mouse, you'll be able to focus more the game itself.
then, buy yourself an external numeric keypad that plugs into the USB port, and sit that comfortably.