If you're willing to cut a new CP and re-arrange everything, I'd say put a spinner in the middle, and move the joy over to the left.
It seems natural to stick a joystick right smack in the middle, but alot of arcade games would offset the joystick to the left (since you're expected to use your left hand).
The only situation that warrants putting it in the middle is when you want to make it equally ergonomic for people who use the other hand for the joy.