Building 1st Control Panel - Need Help

[NGen2010]

I am building my first set of arcade controls.  I want the following:

1 - 4 way
2 - 8 way
1 track ball
1 spinner

I understand the layout with the 8 way controls having 6 buttons each, but can the trackball, spinner and 4 way leverage some of the same buttons or does every control need dedicated buttons?

How many buttons go with the spinner?  1 I'm thinking
How many buttons go with the trackball? 1 again?  2 maybe?  (I see I can order 3 buttons with a trackball, but why use 3)
How many buttons go with the 4 way?  2? 1?

Thanks and I hope to get started on a prototype this weekend. 

This is going with a nice Total Carnage cabinet I picked up.

[DeLuSioNal29]

Yes the same buttons can be used by the trackball and joystick.  No need to have extra ones.  Usually, they are player 1 buttons.  Same goes for the spinner.

However, on my panel I have 2 extra ones for the trackball that act as left mouse and right mouse buttons.  I doubled them up next to my 4 way joystick.  Since they were really left and right mouse buttons, in MAME, I set them to be button 1 and 2 in addition to the normal button 1 and 2.  They work perfectly in MAME, and in Windows, the act as mouse buttons.

As for the spinner, you can use the player 1 buttons.  Games usually only use 2 buttons at the most for spinner games.  Tempest is a good example.  Fire button and Super Zapper.  So you should be all set.

~ DeLuSioNaL