I just bought one OAG too. And it also has this excessive wobble.
The oval hole is way to big.
After tightening the thumbscrews the rear end of my Lodestar can move >1cm to and fro in the direction of the telescope.
It cannot be the intention that the user has to perform bench work to correct this issue.
Sam admits that this is not good.
What do I do to correct this?
Return it to the dealer under warranty.
Just look at:https://youtu.be/6CuBm8Iir48