Beeeeast at bantam. Won series with Herman (top 5 here) Joe Lynch (top 15) Bud Taylor (top 15) and beat Kid Williams (top 10). It's ****ing nuts the damage he did against some of the best bantams who ever lived.
I guess with Zarate, it's a combination of the KO percentage, the (at the time) huge win over Zamora which effectively made him undisputed champ, as well as beating another top couple of bantams in Martinez and Davila and making 9 defenses in 3 years and then the only loss to Pintor being debatable was enough for a place in the upper echelons. I remember the Ring ranked him no. 1 all time which always seemed too high but I figured the edge of top 5.