The layout wont work because of the way the spinner sticks up. It will get in the way of the buttons. Also will
make it hard to operate the buttons and spinner at the same time.
How about this instead:
Mount your spinner Horizontally, to the front of the control panel. So it will be like a Stereo volume knob.
The gameplay should still be comfortable and easy to control... and you save panel space, as well as no interference with other
controllers.
You could even angle the Front egde a little if you really wanted to. You could also make a pull out spinner Drawers, where the spinner
is vertical, and pulls out of the front of the cabinet.
Another more complex solution, is a spinner that sinks flush into the control panel surface when no in use. And or a spinner that has a
button shaped top to it, and actually is designed so that it actually can be depressed and used as a button. (sliding assembly) Then
again, rises up to spinner height when needed as a spinner.
The horizontal spinners are the easiest.. and you could mount 2 or 3 of them for multiiplayer racing games. (use flip down pedals on
the cabinet base)
Pull out drawers would be pretty easy too... and could maintain the vertical feel.
Lastly, you could also place the spinners to the upper left of the joysticks. (diagonally) This would allow left hand to use either the stick
or the spinner, without getting in the way of anything. Only problem, is that it wouldnt allow use of both stick and spinner at the same
time. Usually this isnt a problem anyways... as theres only like 2 games that would require that... and both of them need a trigger stick
anyways. (though, you could use a pedal to fire... but I think your foot would fatigue way too quickly, especially in a stand-up cabinet)
Mad Planets is worth a trigger stick and spinner combo. Very awesome game
Tron and Discs of Tron, both require trigger sticks as well.
(Discs of Tron also requires an up / down spinner. Tron used a special trigger stick that had a rubber guide to make diagonal
movement very difficult to do... so that the light cycle stages were zig-zag free. I believe there are software alternatives to make it
playable with standard 8ways sticks however)
Some other games used spinners that doubled as fire buttons. Only one I can recall at the moment is Forgotten Worlds. I believe theres
another game that used the same type of spinner... it involves some sort of alien theme.
Alternative ideas: Mount a horizontal spinner, so that the wheel is used like a vertical roller. Search for the picture of
the Prototype 'Major Havok' roller controller. In this way, the dial would take less vertical room on the surface. Sits much lower than
a typical spinner.
However, you would probably need some mods to the spinner to make it useable this way... such as use or a softer roller blade wheel top, Or maybe just a rubber skinned dowel. May also need to support both ends to prevent the shaft from bending. A bearing + extended shaft on the non-encoder side would do it.