Flexing a Flex Plate?

I wouldn't do it.
I would measure the TC pilot for being too big.
And the flexplate for flatness.
More work,
I know, but..............

I wouldda just welded a blob onto the ring-gear and spent a few minutes with a die-grinder on it; in situ.
So since you went this far, I can see you're no stranger to, "more work", lol