Good post but many of the boxers in the weight classes from the golden of boxing will be under weight compared to today's heavyweights and other weight classes. Guys like Marciano would be a Light Heavyweight or Cruiser-weight. I think it kind of hard to gauge the best of the best.
Heavyweight: Agreed. Lt. Heavyweight: Probably the 40's and thereabouts, but I can't disagree too vehemently with your choice. Easily my favorite era. Middleweight: Teens/20's or the 30's/40's. Both exceptionally deep. Welterweight: 40's or thereabouts in terms of depth, 70's in terms of top quality. Lightweight: 20's/40's Featherweight: 60's Bantamweight: Anywhere from the 60's to the early 80's. Flyweight: See above.
The thing is, Im not asking about how they would do p4p, only which era's were the most competitive. With all due respect, one has nothing to do with the other.
Heavyweight - 70´s and 90´s Light heavyweight - 50´s Middleweight - 40´s and 70´s Welterweight - 40´s Lightweight - 20´s Featherweight - 60´s and 80´s Bantamweight - 60´s and 70´s and today Flyweight - 70´s
I think from lw to mw the 30s would be competative with any era for the first place. Thing is most great fighters there moved through the weights - very similar to now actually - and only stayed at one weight for a while. Most ended up at welterweight for a longer part of their career though.