I'm not using Mach3, but G code is G code right? The following might help if you can figure how to implement it.
I use a similar setter.
https://photos.app.goo.gl/sQkvtc2VG2aKBsb77
with this code.
Code:
o sub
;
G21 ( use metric units)
;
G10 L20 P0 Z0 ( Set current Z position to 0 so that we will always be moving down )
;
G38.2 Z-25 f150 ( Probe to Z-25 rough position seek )
G91 (Incremental distance mode)
G1 Z2 f400 (Rapid Z up 2mm)
;
G38.2 Z-25 f25 ( Probe to Z-25 slow! )
G10 L20 P1 Z67.473 (set Probe position to the tool setter height)
;
G90 (absolute mode)
G53 G0 (Use machine coordinates)
;
G91 (Incremental mode)
;
G1 Z25 f500 (Rapid Z up 25mm)
;
G90(absolute mode)
o endsub