I think Hoss is doing it very similar in his thread. I'd imagine that the screws are going to wear out the nuts pretty quickly if adjusted to reduce backlash. On mine (a PM-25 not a G0704) I can't get my backlash down to less than 0.006" (originally about 0.011") and that's with the nuts really squeezed down. They used too small a screw in my opinion because my hex keys can't reach on the short side and the long side is now twisting instead of getting the screw tighter and it's getting noticeably harder to crank as I tighten down.
Anyway, I think it is a reasonable way to boot-strap and allow you to make more sophisticated parts for the better conversion later. Looks like no matter what, if this is the only mill you have that you may need some outside services to machine clearance under the table for the ball nuts.
I plan to go that route too and I'm waiting to see what Hoss puts together as phase 1 of his conversion. The quill-friendly belt drive he is making is at the top of the list too, mine sounds like a rattling beer can in low gear if there is any interruption to the cut. I think the gears have way to much free play back there.