BF20 Z axis question

G'day everybody.
I'm not 100% sure whether I want to do this or not, but I'm currently thinking about CNC'ing my BF20.
I'm just in the brainstorming stage, and I'm not really one for copying exactly what other people have done or buy plans or anything like that, I much prefer to try to figure it out by myself. But I do appreciate any input from other people who have been there and done that before.
So this is where I'm at for the Z axis:
The original top plate on the column is about 23mm thick. It has a recess in it that is 17.5mm deep and houses a 17x40x17.5 double row angular contact bearing.
I'd like to continue using that double row AC bearing, and just add a single row (7203) AC bearing on the underside of the top plate. Pretty much exactly what I have in the attached pictures.
I'm not sure I like how that single row bearing is sandwiched between the top of the ball screw thread and the underside of the top plate. I can't see how it wouldn't work, but there's just something about it that's bugging me.
I don't want to pull the mill apart just yet because I have a few jobs for it, so I'm just assuming that as it is, the through hole diameter on the top plate is larger than the diameter of the inner race of the bottom bearing so it's free to rotate.

Does anybody have any thoughts, criticism, or anything else for a configuration like that?

Attachment 481978 Attachment 481980 Attachment 481982