I don't think it matters, but experiment it you can before permanently mounting them. You should be able to get the set working before bothering to make a new yoke cover.
Also it will work fine without the rings at all. You only need them to tweak the image so it's centered in the screen.
I show one way to fabricate a yoke cover with centering rings in this video:
https://youtu.be/UXyra3vNYuQ