I would suggest starting with
@Spacefruit's site, Speedmaster101. For me, it was the best read when getting into Speedmaster's and in understanding the vintage versions and what to look out for.
I then went on to purchase the book to read though the history and goes into greater detail on what to look our for.
I haven't found the vintage grail I'm after yet but I must refer to either resource at least every other week.
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