there's really only two parts to the chest. pec major (upper) and pec minor (lower). after years of doing just incline db and flat db with incline db flyes (now weighted dips) my chest is fully developed. upper, mid (whatever that is), low, side, middle, upper outer corner, lower outer corner, inside corner, lol. i dont think you need 25 sets but you know your body better than i do.