Dan ..... Here's the page of a thread showing mods done by Errka with pics of the bolt and plate with spring washers .... https://rennlist.com/forums/928-foru...f-into-18.html

Read through to post #278 on the next page where he gives answers to the questions I asked at the time re the exact setup and hardware used. I followed that detail to get the same great result, that locks it in the correct adjustment position, but still allows you to revisit the adjustment later if you want to.

I prefer this method to drilling holes and putting in roll pins to lock it.