Aha! I found the answer
http://forum.arcadecontrols.com/index.php?topic=3131.0X-axis makes your mouse move horizontally
Y-axis makes your mouse move vertically
Z-axis is like the scroll wheel on your mouse
I want just X and Y for this trackball
Yellow = X1 = A on Opti-Wiz
Green = X2 = B on Opti-Wiz
Brown = Y1 = C on Opti-Wiz
Blue = Y2 = D on Opti-Wiz
Red = +5v = 5v on Opti-Wiz
Black= ground = symbol above 5v that looks like this :

And that looks like this :

When I tried the trackball out in Windows XP the mouse cursor was inverted, the cursor would go left as I was spinning the ball right - so I flipped the trackball in it's plate and tested again, it worked fine.

I know MAME is super configurable so I will make player three's buttons as mouse buttons that can work within Windows and also be set to work within MAME - this acts as a mouse built into the control panel for using in Windows.
On the button's microswitches "NO" lugs connects to "L" and "R" on the Opti-Wiz, and "COM" lugs connect to the nearby ground symbol.


Hot glue is nice for holding wires down, and removable in the future if necessary.

And that's a wrap