I haven’t used this code in quite a while because it only kind-of worked on Smoothieware, Smoothieware is barely supported now, and so I gave up and switched to Marlin. Worse yet, there was a github fork that I deleted this year and I deleted my local copy of the fork.

So, I’m sorry but I don’t think I can replicate this.

Or, if you have a RepRap-compatible controller the RepRap software supports multiple Z drivers automatically.