Turns out my car came with a 15/16" master, so I can't confirm that the 13/16" were ever put on early models.

(Luckily I used a mirror, instead of removing it to find out!)

So, looks like I might try to squish in a 17/16" afterall.

Now, I'll have all kinds of time to talk about DSMs, because I won't be busy fixing mine!