So I've been a little recently frustrated with an abrupt lack of response from these "TEN-HIGH" vendor on Amazon (before CNY- which I realize is now but this was before they had an excuse) regarding my X axis screw which I have saved for last on my machine retrofit. Still, I'm eager to get that done after my Z and Y axes turned out unexpectedly well.
I use this machine for occasional prototypes in the course of product design, not any heavy or industrial use - I frequently also use it as a manual machine.. That said, my X screw is going to be around 900mm (including end machining, and the last 4" of thread on either end won't need to engage because of the large carriage/motors/etc.

I was all settled on my purchase and upcoming challenge of installing it, when I discovered double ball nuts. In this application I have plenty of room for one without any real consequence, but it seems to be a rare offering from the manufacturers in China. I worry about the length of the screw and the additional load it will have to carry compared to the other axes and so I'm thinking if I can find a double ball it might help alleviate some of these anticipated issues. The threads I've found here seem to validate them at least in concept- I don't mind doing some extra modifications to tighten them up, as I will have to modify nearly every other part anyway in one way or the other.

Similarly, although they provide the kits with bearing blocks, I was looking into maybe spending a few more $ on a bearing upgrade as I'm sure they use the cheapest option. Has anyone tried that and do you think any of this would be worth it? In some ways I feel like its lipstick on a pig, and I'm not shooting for a world class machine- just a substantial improvement over the lead screws that were originally supplied. From another perspective though, for a few extra bucks now, if I could increase my reliability and precision I can probably convince myself its worthwhile. Just looking for a good balanced bang for the buck. Thanks for any opinions, figured I may as well use this delay as an opportunity to do more research.