The pins shouldn’t pinch the hairspring at all. You want to have a very small space for the hairspring to vibrate in, The spring should move back and forth in this space and should make contact with both pins but only one pin at a time. The pins should also be straight and not at an angle. If you go into the Ultra (or Watch) course and then scroll down and click on the orange link that says ‘Timing’ you’ll see a few diagrams about half way down the page on how the pins should be shaped.
Hope this helps Steve,