Yes, we now know that you don't worship Campagnolo. You've stated it. Twice.
I don't either, really.

Though I was loath to respond to post # 12, which I considered somewhat pejorative and even a bit superior in tone... I think a short rebuttal is in order.
Despite the risk of hi-jacking the thread.

If you think the reason I went to all the trouble of doing that project was out of vanity, Chas, boy, do you miss the point. I suppose I may have preferred Campagnolo Record components at one time in my life out of vanity, that was a long time ago. I like them now because I think they were, overall, the best component group ever made. The best shifting? Nah. If that was my only criteria I would have Suntour derailleurs on all my bikes. To me, though, there's more to the allure than that.

I do still have the original Simplex Criterium derailleurs that came on my Gitane. But the plastic in them is now 44 years old and I'd prefer to keep them in the good condition they are now in. I may sell that bike some day and if I do, I'd like it to be original. I only have one Simplex rear. I have many Nuovo Record derailleurs. Record derailleurs don't break like Delrin Simplex do.

But the main reason I did that Simplex dropout to "standard mount" derailleur was just to see if I could. While I realize that just tapping out the hole in a Simplex dropout to accept a standard mount derailleur is a quick and easy way to use another derailleur, I didn't want to do that to my frame. Others don't mind it, I know. That's their choice. But I consider doing so as forever altering a vintage French frame. Not as radical as hacking off the hanger to mount a claw, for sure, but still an alteration of a classic frame, which I personally find just a bit sad.

Of course, the custom mounting bolt method is not for everyone. Nor is it meant to be. I just did it for my own sense of satisfaction. It's highly impractical.
But I knew that going into it and that's OK with me.