I do it like this
F_HOME
M05
G04 F1
STOPRE
T= "GREIFER"
G00 X100 Z=-R99+12
G01 G94 F6000 Z=-R99
G01 X0
M69
G01 Z0
M68
G00 X100
M01
F_HOME
M17
With polygon material you should program a spindle positioning after the STOPRE
e.g. with a square SPOS=90 or hexagon SPOS=30