I got almost as much backlash as with the stock screws, and the backlash varies, as the nut travels down the screw. I don't know if it varied with the stock because I never checked it.
I have Roton ballscrews, and the play is 10 thou. with a little bit of wiggling to get there, like the balls are pushing into the groove, or something. The Roton website says the O.D. is 0.625, but mine are 0.612.