In the shipping docs I got with my A101-1 it says the Z steps/mm is 756.00.
This is confirmed in the .h file in the Marlin code.
How is this number determined?
The leadscrew is 20 tpi, that’s 1.27mm per rev.
With a 200 step/rev motor that comes to 629.92 for 1/4 stepping and 1259.84 for 1/8 stepping.