I'll be interested in your continued testing of the panel if there is enough room "below" the player's 1-4 controls to rest your wrists on. It seems pretty tight, but might be enough.
I've got about 7 inches below the controls on mine and I know after continual playing I enjoy being able to rest my wrists there, very non-fatiguing. I know it is not "arcade-accurate", but how long to you sit at one game in the arcade. Not like on the MAME machine.
Good job though, looks nice. Hope you enjoy it now that the CP is done.