There is no such thing as primaris, its just different armor version.
Veteran marines
Secret for cutting is as always
1mm on the base under the gravel
1mm added to feets
1mm to the waist
1mm below waist, – this one is tricky as it depends of the pose where to cut, there is also more greenstuffing involved and filling, but there is not many of the veterans in the army so its ok.
Could you do some WIP photos next time to demonstrate exactly where you add the extra material?
Yup, preparing that ATM, will leave for whole week, so probably will upload it no sooner than 30th, but will try.