PLEK update:
First, to stay on topic, a Thunderbird is my primary bass.

As a follow-up to my previous post about getting a 1988 Ric 4003s PLEK-ed, I got the bass back and am thrilled with the results.
The bass plays exceptionally well and I got a report about the process as well.
View attachment 4992699
As other mentioned in the original thread, the final fret polishing and set up are done by a person, so it is a combination of the two that makes up the final result.
In my case the frets (1-7) were significantly lower than the remaining frets. This is part of what was causing me such difficulty in getting it set up properly.
This process was done
after taking it to a local "Rickenbacker Specialist' with 40+ years experience for set up and nut replacement (original nut was not on the bass). This tech slapped on a new RIC, pre-cut nut and called it "done". It had not been filed for string height, there was zero mention of any fret issue and the new nut was too wide for the bass, as newer Ric's have wider necks. This put the E & G strings really close to the edge of the fret board.
It was $239 all in (including new strings) so not cheap but about $100 more than a regular set up with strings in this area.