I'm just planning my next project which will be a 3/4 mini cabinet. The CP will be 19.5" inches wide as that is the width of my CRT monitor. (IIyama Vision Master Pro 514). I definitely want to play Robotron and Smash TV on this machine so it will need 2x joysticks. And with that I may as well make it a two player cab. However I don't play fighters. I'm more of a classics gamer.
So my main question is how many buttons should I use for each player? At the moment I'm leaning with three on each side. But I've seen those Neo-Geo cabs with four for each player. How many games in Mame use 3 or 4 buttons per player? I remember a utility that filtered out lists like vertical, horizontal, 4-way, 8-way etc.etc. and for the life of me I can't remember what it was.

I'm thinking of putting the joysticks centrally on the CP (in other words the sticks will be placed just like a Robotron/Smash TV panel) so that the players hands are central to the screen, just as they would be on the original cabs. But that means that Player 2 buttons may look a bit too far to the right side. I suppose I need to make a mock up first and see how it looks. I might even place a spinner in there if there's comfortable room. Certainly no trackball though.
I also intend to use a beefier PC for this project as I want to use Hyperspin as the FE. However I have come to love the UltraMap plugin that is availble with Mala. Can Hyperspin swap control maps on the fly for the U360? Or is this a Mala only thing? If so then I will stick with Mala as that brilliant functionality is much more important to me than the improved graphics of Hyperspin.