These things are what you put on paper to repair ripped holes from binders. I forget there name but they actually work pretty well. I must warn that they are a little big then what would be ideal for making circles on these shoulder pads. But until i found a better template that holds to the pad ill make do with this.
As you can see I situate it as center to the pad as i can and gently press it down onto the shoulder. Its meant to stick with paper doesn't have a strong bond to the plastic. This is good because when you take it off it wont leave any residue or take any paint. Just use the inside circle as your template and make your circle.
And that's the finished marking after the template is removed. It is a little big for a shoulder pad but it works. This will work even better on vehicles and dreadnoughts I would imagine as there are more flat surfaces to use this on. I have no tried it on a metal surface and I do not plan to as my goal for this crusade era army is to be all plastic.
Once i have this marine finished ill post shots of him as well.