Agree....
Why would you even consider letting them "hold you hostage" for that obscene amount of money?
Mays' current signature doesn't even resemble the 1960 version. And even if he signed flawlessly (a big "if"), it would stand out like a sore thumb, and subsequently ruin the ball.
You have a very nice vintage piece there. The stamped Mays signature is part of the Ball's heritage, so try to be content with that. There are thousands of other Mays signed items available at a fraction of that outlandish price. So if you must have a modern Mays autograph, try to obtain one without corrupting a great vintage ball or paying 20 times what it is worth.