Im restoring my old sash windows in my house. I'm thinking about doing outdoor sealed storms and indoor sealed storms to help with inefficiency. I was wondering what would be a better weather stripping for the windows. Spring metal or Kerf in Pile weather stripping. Im leaning towards Kerf in Pile because there is no window weights. There are spring loaded pins that hold the windows at certain heights due to hold drilled in the window jams. If I did the metal spring weather stripping there would be a hole in the middle one each side of the sash to allow the pins to go through to go into the holes in the jams. The Pile stripping would be on the outside of the pins and being kerfed in would keep them in place and keep them on par with newer windows. What are your thoughts?