Question on zeriong with the KAC micros. 6.8 spc ii

OK so using a 25 meter zero target at 25 meters I am curious what to use on the KAC micro rear to zero. With a standard m4 we would use the z marking on the optic. Would I set this on 250 as 250 and 25 meters are spot on? Ik the sights are calibrated for the m855, just wondering how far off they will be.

I have the KAC Standard rear which is designed to be zeroed at 50 ft. (50-200) with is the Z mark on the sight. You dial up from there depending on distance. Why not zero using the Frank Proctor 10 yard zero target for 50 yards–a 50 yd. zero? Or am I misunderstanding this?

Ballistically a 25 meter zero with the 6.8 equals around 200 meter zero. It gives me around an 4" drop at 250 and 11" drop at 300 meters.