Great results!Yes, the dimensions that I measured are within .01mm of what @4nthony posted, but in this application, only 2 of them matter. The ones at the top of that diagram are all we need here. Those are the ones I was saying are off center.
They are bigger holes (6mm threads) and do not contribute to holding the original base in place.
The OF1010 has similar holes, thought they are closer together and centered.
The combo/adaptor only uses these 4 holes.
That's kind of the beauty of this, you don't have to remove any of the original tiny screws.

I checked on Shaper Hub and could not find the files.
When you have a moment, could you post the link please. Thank you!