Hi Julien,
I've just come across this post.
The aftermarket insert you have there, it may bee fine sanding to get it to fit.
If I were you, I would keep the proper Heuer tachy bezel bezel on it. Just out of interest, how do you know that it was originally sold with a min/hour insert and not a tachy?

Stewart

: I'm just a maniac who likes to have his watch exactly like it was
: when sold for the first time.

: This is called in finance PIT for Point in Time, the ability to get
: an information exactly as it was the day and year it was first
: released.