When the Ring magazine had an all time tournament to determine who was the greatest flyweight Canto won it. I've no idea who was the best ,but would put it between Canto,Perez,Wilde and Lynch.
Hard fight to assess. I reckon Canto could nick a close decision, but Perez was quicker and more adaptable than Betulio so it could be a boxing match just as much as a ‘boxer vs. aggressor’ type of thing. Perez could definitely dig as well. Both top 10 flyweights of all time (arguably both top 5)