We run the restrictors a bit tighter than yours is and never had an issue. Juts trying to keep oil down low.I have been down to .025". On ereason for the bushings is what you just found. Toss a liter from a broken rocker or badly broken spring and you still have pressure. The problem then will be the link bar. Why I like to use keyway stuff but overkill for most everyone.

Things happen when racing.