I have to laugh about all this jibberish about edge finders .
Any will get you within a half thou easily . You want better , tram the edge with an indicator . We're not making rocket parts here . If you were caught using an edge finder on our Deckels or P&Ws , you were walked out the door .
As far as the Starrett center finding sets , they'll get you close enough although never perfect as it picks up only one edge ( leading ) of the hole OR the countersunk hole . In any die work , you need thread plugs and a .0001 Bestest or better .