Help identifying vinyl glazing bead, please!

Hi, I have aluminum frame windows from the mid 70s and having a hard time finding the proper vinyl  window glazing bead. Have bought a couple things on line from Grainger and another, but, while they are darn close, do not snap in properly. Attached are pics of a piece taken from the windows and a dimension drawing of what I can measure with calipers. I can mail a piece of this to you if it helps. Hoping you can ID this bead and, even more so, hope you have or can get stock! Thanks for your help, James