I have to elaborate a bit on my vote...I picked Canizales, but this would have been a hotly disputed decision, with Canizales suffering a brief kd,...and Castillo, bless his heart, would have been able to secure a rematch I'm sure. I have to ruminate on the results of that rematch.
I was in awe of him as a tough guy...a good, smart, savvy tough guy. I read about the first Mexican shoot out, as they called it in SI....when Castillo made it to the bell, and as they said, "walked out of the ring under his own power", unlike all of Olivares's other victims. There was a picture of him in that magazine article, showing him doing that very thing...walking past the crowd, proudly wearing his big ol' sombrero, being cheered by a respectful crowd.
Chucho fought out in those LA boxing arenas where 4-5 bantamwt. fighters could have been THE Champ on their best night....in that era.