Reply to DIY MF Brainstorm

My gramps is going to be in town in a few weeks, and although he's getting a little shaky he's still a God at Machining and DiY bliss. I'd love to be able to have some time to work on a project with him, so I'm plotting out a mod that would encase two of my midifighter...

I haven't made much ground, although I plan on upping the button size and using a layout that I'm a bit more familiar with (I play fighting games and my arcade controller has 30mm buttons). Attached is the button layout I'm believeing of. I still need to add some effects control (super faders), levels/EQ section, and an headphone section. I'm brainstorming, so any ideas on mapping, how to position things, how to structure the top section of my controller, etc would be much appreciated

I'm also knowledgeable in some programming languages, so multiplexing and rewriting some firmware shouldn't be too hard.

Left hand buttons mirrored on right
Delay Kill Pitch Bend - Pitch Bend + Cue Play/Pause
Slicer Mode Cue 4 Cue 3 Cue 2 Cue 1
Thumb Button = Shift

Left hand shift buttons
Delay Kill Pitch Bend - Pitch Bend + Cue Play/Pause
Layered Sample Deck Toggle Slicer Value Ditto Ditto Ditto


TL;DR: Help me believe of some ideas for this controller.