RBC screw/nut disassembly

The screw is new, but has about .005" backlash, I tried everything else i was advised of before coming to the conclusion that it was the screw itself. It's for a knee mill, y axis. I want to take it apart and increase ball size to try and remove some of the backlash. I have a Bosch Rexroth screw that was very easy to take apart and reload, this one I'm not 100% on what to do. I turned a mandrel for it, that is something like .010-.015" smaller than the screws minor diameter. As seen in the pictures it has 4 pickups, so after removing the end seals, and unscrewing the nut onto the mandrel, pulling the mandrel out and measuring the balls, how do I reload this type of screw? Also can you recommend how much I should oversize the new balls, I was planning on using the alternating technique, new big ball, old small ball etc etc