i think the amount of overhang is more a matter of comfort than playability. when i'm playing i tend to rest my waist against the cp(or pretty close). the overhang allows my feet and lower body(bent knees) to sit under it without hitting against the cabinet. what i'd do in this case is mock up your design with some cardboard, then test it out. if you feel it's comfortable, go with it.
i'll also mention, i have a tron and galaga that i've got in my room here, both have little or no overhang at all. i think we all can agree, these games play pretty well.