I had to expand my search but I found the thread where the original stripe was measured.
I just used "accent stripe" But like any search engine you sometimes have to play the combinations
This confirms where some people had indicated it was about 1 inch from the top body line. I have heard a lot of people say the stripe was 3/32 wide but the measurements in the photo show 1/8 wide. I really suspect since this was put on manually in the plant that each plant and each person who put them on will be different.
Don't believe it would vary that much they used a pinstripe tool to apply them. It was a small metal container with a felt wheel that applied the paint. If pressed hard the felt wheel would be destroyed or wobble creating anything but a straight line. By the 60's they were not free handing like what was done in the 40's. Same sort of tool was used to stripe around the Boss 302 hood black out and original examples of those seem to be very close to one another in width. If they had been done by hand you would have seen allot more tapered ends on factory pinstripes the tool left a dull somewhat square end when lifted
The sold the tools at every swap meet and you would see ads for them from time to time in magazines. Think we had one at one point though they were frowned upon by the traditional pinstripers
The photo with CS shows the stripe much closer to the top body line then the unrestored fastback. I have seen this on several other photos in magazines and posted photos from other sites. I have also seen the same 1 inch distance on other photos where they indicated the strip was factory original
Guessing that the most of the pictures you've seen are on cars that have been redone. IMHO not always the best place to get your info. Best would be to find other examples from the same year and plant to find what the couple of guys were doing there at the time