Well, I went and gave it a try. I put a freq counter on my signal generator and followed the directions.
The slugs only needed a half turn or less (if at all). There is a noticeable difference in resolution and the sound is clean. There were a couple tube shields missing and it was obvious what a difference they made in the VTVMs reading.
This is turning out to be a fine running set. I struggled with a vertical frequency/ hold issue that turned out to be a mica cap that was skipped during my standard recap. this set is a Bakelite tabletop model, I'll post some pic's soon.
Dave