Ugh ok. Now that someone else opened the door I guess.
I’d suggest getting some pegboard or thin wood and making a template-/ cut out the holes and mount the controls and test play that. Try playing some of those inner controls.
I have been there, done that, bought the t-shirt.
My first cab:

I had the ‘old crotchety members be damned, I’m doing it anyways’, and that cab was still pretty early on in this hobby. And I regretted it.
Those inner controls, and even the dedicated 4-way NEVER got used. By anyone. Including me. (And I don’t mean rarely, I mean literally never). It is not fun, or comfortable, or even sane to try to play a game while reaching over other controls to do it. Back strain? Yes please. Rest your forearms down? Oh ---steaming pile of meadow muffin--- I inadvertently hit 10 buttons. Forearm hitting other joysticks. It’s super fun to get speared right in the middle of your forearm too. And a smooth ball doesn’t feel any better.
Those inner controls you will use for like 1% of games. And they clutter your panel. And the thing you will 100% regret the most and that will turn people off from wanting to play is not having a 4-way in the p1 position. People will NOT want to reach in for a 4-way, and playing Pac-Man/DK/anything 4-way on an 8 way is not doable. People get pissed and are like ‘this sucks’ and don’t play. And most ‘oh cool, an arcade cabinet” players want to play Pac-Man or ms Pac-Man. .
Even If you want to keep all the other stuff, I would HIGHLY, HIGHLY recommend putting a servostik at the p1 position that automatically switches between 4 and 8-way. And no, an ultrastik 360 with a 4-way map DOES NOT play like a physically restricted stick. I had one. Trust me.
—-
Wasn’t going to get into it because the design looks dope and I would like to see it purely for aesthetics, but now that the cat is out of the bag I would feel bad not at least TRYING to convince you to not do it.
As boring as it looks, this has been the most useful, best layout I have ever had. I have had at least 10x more play on this than on any of my other cabinets:
