I am set on making a spinner control panel for my desktop.  What I'm trying to do is make a decent panel that covers most of the
games that use a spinner.  I looked for a list of games, but unfortunately I came up with nothing (anyone know of a list of spinner games?)
I want to play at least Tron, Tempest, and Tac/Scan with it, so I figure the best layout to start with is Tron's.  So I'll get a top fire joystick and put in that on the left side of the panel, and the spinner on the right.
Now I'm trying to work out how many more buttons I want with it - aside from 1p/2p/coin and maybe a little pause button, how many gameplay buttons do you think I'll need?  Most shooters only use 1 button - and I've ruled out playing driving games with the spinner (I saw some of you guys do it but I prefer a wheel setup 

) and I don't want to use the top mounted button on the tron joystick for games like tempest.. How many "fire" buttons next to
the spinner would you guys say I'd want?  I know I've forgotten about some games and I don't want to start building until I'm sure of all the buttons.
Oh!  One last thing.  Laugh if you will, but there is this adult pachinko game in mame - sure some of you have played it 

  It's pretty fun - I am trying to determine if the spinner would work well for that also.. Seems like it would.  I also reasoned that most real pachinko games snap back to position so maybe a driving wheel would work better?  Any thoughts?