Skip Baldwin does a good job with jeweling.
https://www.baldwinboltjeweling.com/Good jeweling means consistent spacing, logical placement of rows. For instance on something squared off I would expect even spacing on both sides of the object. On a round bolt I would look for jeweling marks that meet well across the round body.
I can’t say the difference between good and average. I suspect most guys that perform jeweling do a good job because not many guys do it.
