Looking at the drawing is seems over complicated.
If you want zero backlash and don't want any movement on the support bearing just go for a good quality FK12, the gten R1605 ballscrew and the R1605T3-FDID-P1

This is the link to the datasheet for the FDI and FDU type ballnuts and it is 34mm between the flats, so it is actually 6mm difference.
http://www.zappautomation.co.uk%2Fpd...%2FFDU-FDI.pdf

The ballnut is already pre loaded for zero backlash and has been tested on the screw.

you will need ti install chinese fonts in acrobat.