You are all doing a good job explaining the principles.
- It was me who assumed X and Y -axis ballscrews are put together in similar way.
- Assumed too, that idea is to make it as sturdy/rigid as possible.
- There are some gaps in my knowledge, filling the gaps with assumptions doesn't always work

But it will be good. Will create another drawing of the ballscrews -setup.

Thanks again for comments!