Looks like a very practical layout. That will serve you well. In fact it looks a lot like mine!
My one concern would be the proximity of the P2 joystick to the trackball. Right handers may have a little trouble with that. Maybe move the joysticks & buttons a couple of inches up, and drop the trackball a couple of inches closer to your body to remedy?
Also, I would move the spinner a few inches to the right, over the P1 buttons. When you rest your arm inbetween the P1 joystick & buttons to access the spinner, you will want it off set a bit to allow your wrist to bend in while using it. Added bonus is right handed spinner ppl will recognize the same benefit when resting their arm between the P1 buttons and the trackball.