go here. get the guide rod and 11# spring set for 25 bucks. the 11# rate is factory, but the dual spring set up tends to be progressive, while the sigle spring is constant. don't know why, but it makes a difference.
or, call cylinder and slide. they used to do "tune ups" on the mustang and pony that included spring sets and action job. they'll also meld the edges. at least, they used to.