Thanks all,
And especially for the custom pic Blanka!

I figured I could add some washers to keep the screws extended, but didn't think that I SHOULD be doing that, so asked in case I was doing something blatantly wrong. To answer the other questions:
- Screws are going as far as they can, and they cam with the ball, so ASSUME that they would be right size?

- Ball CAN be flush to the topmount IF I hold it up with my finger
- Doesn't appear to be catching or against the wood, I left a little room around with my "precision" jig-sawing.

I'll add some washers and wire tonight! (Hopefully)