I think most people offset the sides just to get a little more travel. You really don't see any commercial machines that do that.
In your green version, you'd be better off bringing the back straight down, spreading the bearings further apart.
Depends on what you are doing with it.but is the Z loading significant or worth designing an offset set of supports?
This thread has a lot of good info in it.
https://www.cnczone.com/forums/diy-c...cad-posts.html