Z-plus parameter settings, anti-backlash nut, and wear

[downrazor11 (Stephen)]

Hi everyone, I need a little insight to the relationships involved in:
-the $122 (z-acceleration) grbl value,
-the wear it induces on the anti-backlash nut on the lead screw, and
-the z-plus assembly (specifically how to physically replace or upgrade the anti-backlash nut).

First, my machine: an SO3 (2017), with the z-plus upgrade (about 5 hours of runtime with the z-plus at this point), 5/8" ATP5 aluminum plate wasteboard, using steel-core belts on x- and y-axes, running CM 521 on Windows 10. My machine is square, and calibrated with respect to the $100, $101, and $102 values.

I have measured the backlash in my z-plus at 0.04mm (for a reference point, standard 20lb printer paper is ~0.09mm), which is within spec for the z-plus. My method is described in this thread here. (As an aside, it would be nice to know what backlash value would be considered out-of-spec, for both the z-plus and the HDZ.)

My main questions are:

1. What parameter settings (or processes) induce the most wear-and-tear on the anti-backlash nut?

2. My understanding is the greater the wear, the greater the backlash value, is this accurate?

3. I have also read that increasing the acceleration value for $122 (z-axis accel) generally increases cut quality and endmill longevity, but decreases the service life of the anti-backlash nut. If the default value is $122=270, is there an acceptable range for acceleration (for example something between $122=150 to $122=400)?

4. What happens to the SO3 in terms of machine wear, endmill wear, and workpiece quality at the extreme ends of the acceleration spectrum?

5. And, finally, when the time comes to upgrade or replace the anti-backlash nut, how can I successfully do so (diagrams or pics) without, I’d assume, sending it to Carbide 3D? Would it someday be possible to order a replacement anti-backlash nut from Carbide 3D?

Thanks in advance!