Dug through my derailleur stash and came up with a Suntour 7 from an '81 Univega that will clean up nicely and it has the integral cable housing stop like the Simplex. It will do until a more suitable replacement can be found. I also have a nice Cyclone Mk II that has the stop as well but it's part of a matched set and I don't want to split them up. I've decided to fast track this one as it will be the easiest build of any of my recently acquired Reynolds 531 bikes and I'm anxious to ride one.
__________________
".....distasteful and easily triggered."