Size matters, obviously, in Tier 1. But, era matters, too, especially since you specified 40s through late 60s. Bonannos fell apart after the Commission removed Joe in the early 60s and replaced him with DiGregorio, triggering a long, destructive internal war, a series of mediocre Dons and the loss of their Commission seat. They didn't get back into Tier 1 until Massino stabilized things in the 90s, and they got back onto the Commission with help from Gotti.

Trafficante could have been near Tier 1 until '59, when Castro nationalized his casinos and cut him off from his source of money and influence. Then he became strictly regional.

DeCavalcante may have been more powerful in the 60s than most thought.