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About the buttons around the spinner, I was mainly positioning them for the trackball and hadnt thought to much about the spinner, do you have any recomendations on where I should move them?
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for games with the spinner in your right hand, i can't think of any games that require more than two buttons. the most popular of these games is probably tempest:

for games with the spinner in your left hand, blasteroids requires three buttons:

and some require four (victory, star trek).
given unlimited space, i would lay out spinner buttons like this:

there is enough room around the spinner to rest either hand on the panel surface while operating the spinner, and there are enough buttons for most games. the leftmost button is not strictly necessary, but it would enable the layout to play asteroids, and it provides a pleasing symmetry.
if there's not enough space for a layout like this, buttons elsewhere in your layout will have to take over some or all of these responsibilities.
as always, verify your layout with a full-scale print-out before actually constructing a panel.