@rfinnie I guess the min/max values are not a strict specification, thus I said "should". It depends on brand/model as I learned (mine Logitech Rumblepad and a knock-off Switch/XBox controller report in the "should" range).
On a tangent: The Arcade'81 looks nice and gives you at least enough space to add a subwoofer. I added an external subwoofer 6.5" later to my custom bartop which made the games even more fun to play. In any case: Happy tinkering!
But back to your initial request/idea. Maybe @pjft can comment on that, if a or which suggested change (see first post) would be accepted in the ES source tree.