I know Matthew Bain back from my days in Miami, actually just saw him a couple of months ago, sporting a 6542 on a leather strap.
He and Massimo Barracca used to own a store called "Senzatempo" that had an upstairs office with some of the finest vintage time pieces.
I bought a couple of Submariners and a GMT from him then and saw my first 6154 in the wild at on of the soirees at the store.
Wish I had known more about watches then, could have picked up some nice pieces in the 90's
Today they both run watchcommander.com and have (co)written a few books on collector watches.