Looking better but I'm not a fan of ballscrews being up above the rails due to being easy to damage thru leaning on or when loading material etc.

Also if those black things connected to the screws are steppers and your thinking to mount them like that then your in for massive troubles.?
Try to build in some adjustment for things like ballscrews to ease alignment.

The bearing spacing isn't too critical when using twin screws so your size will be fine if it fits better. Thou more won't hurt if possible.