Excellent thread OP and as someone said earlier this forum needs some better thought out posts like this. For mine it is Ali, Duran and Monzon probably in any order. But as posted earlier I went for Monzon.
There was google archives that doesn't update any more but had (or maybe still has) lots of good stuff. Aside from that it's subscribing to websites that either have back issues or e-copies
I go with Ali. Only quibble I have with the post is your MW greats list didn't include RJJ and Hopkins. RJJ smokes everyone at MW, including Monzon.
Duran, for the simple fact that he was great throughout the entire decade (as well as being the best fighter of the lot, regardless). Monzon retired with 3 years left, Ali was shite during the latter part, Gomez didn't get his start until half-way through, and Arguello didn't hit the big time until a few years in.
Between only two fighters: Muhammad Ali and Roberto Duran. Ali fought the better comp, Duran was mire dominant. Ali was the best of the 60's hands down!
The only reason Griffith is in the discussion is because of Ali's layoff. Monzon in the 70's was not more dominant than Duran, and he didn't fight Ali's comp. Monzon exceptional fighter made his name beating smaller, good guys. Monzon beat some stiff comp as well at mw, but who was the other dude?