Datsun Roadster Forum-311s.org

spl310 and notoptoy: Thanks for the feedback.

Since my original post/question, I examined two other SRLs and found their twistie centerlines to be ~7/8" ~1" back from the door seam — validating your thoughts about (combined with the non-OEM, double exterior screw twistie) that my twistie is not in the "correct" position. Eventually, I'll replace this abomination with an OEM twistie (which I now understand is mounted with a single, concealed stud) in the correct position.
I've decided to place the grommet accordingly (stitching be damned).

Wherever your twisties and posties are that is where your top holes go.
That is why if you buy a used top it might not fit, every car can be a little bit different.
See where the top ends up after centering, pulling out wrinkles etc and that is your fit.
It is harder than you think but still doable, though some swear they will never do another top again.
I was frustrated and it took along time, but that is often the case anyway
Linda