Here’s the build thread for the Z axis, it has a few more pictures in it: https://forum.lulzbot.com/t/adding-openrail-z-axis-to-a-lulzbot-taz-4-5/2108/1
Basically, the stock Taz Z endstop target uses an M5 bolt with a thumbscrew cap and a spring to set the bed height. The Z endstop mounted on the X carriage comes down, hits that and stops. The issue I found with it, and it isn’t nearly as bad on the 4/5’s as it was on the 3 and earlier, was that repeated impacts, vibrations and heat cycles would cause the spring to push up on the target and raise it slowly over time. That’s why a lot of 3d printers, the Taz in particular have at least a partial reputation of needing to readjust the bed frequently. To eliminate that entirely, and give myself greater starting layer height control, I replaced that M5 screw and spring arrangement with an actual Mcrometer body as an option. You can also still use the M5 bolt approach, which isn’t bad these days, but for ultimate precision where you will never have to change the bed level again, the Micrometer is the way to go. The tricky part is finding the micrometer body, and then finding one that doesn’t cost an arm and a leg.
As far as the anti backlash module goes, that particular unit will not fit the Taz leadscrews. You would need to switch them out for a less accurate threaded rod, which means firmware changes, etc. There is actually an anti backlash nut designed for use with those leadscrews from the factory, but it costs $234 per leadscrew from Mitsumi, and I haven’t even seen anyone else who carries them.
I’ve thought about building an anti backlash nut into my anti z wobble nut mount, but there isn’t enough room to do it without losing 20mm Z travel at least. On my leadscrews anyways, I don’t seem to have very much detectable lash at all, so it hasn’t been a high priority for me. The easiest way to add one would be to get a second leadscrew nut, trim it down, run a compression spring between it and the main one, then lock the second one to the main one via some pins. I’ve tried that before with my AO-100 and it works really well, just takes up space.