Somewhere in the second half of the top 10. I don't have Saddler and Pep as #1 and #2 though, Saddler is probably more around the #5 or #6 spot for me, with Pep in the top 3 (all things considered).
I find him hard to rank due to the fact we only saw him at his peak. For example, how would Don Curry have been rated at welter if God forbid something happened to him before he fought Honeyghan. What about Sugar Ramos if he hadn't been around for the Saldivar fight. Nobody even talks about him now. Not disputing he wasn't a great fighter though. My no1 at feather is Pep.
Number 10 IMO: 10: Salvador Sanchez 9: Joey Archibald 8: Azumah Nelson 7: Johnny Kilbane 6: George Dixon 5: Henry Armstrong 4; Eusebio Pedroza 3: Abe Attell 2: Willie Pep 1: Sandy Saddler Honorary mentions: Young Griffo, Terry McGovern, Jim Driscoll, Benny Bass, Bat Battalino, Hogan 'Kid' Bassey, Davey Moore, Sugar Ramos, Vicente Saldivar, Eder Jofre, Antonio Esparragoza, Naseem Hamed, Marco Antonio Barrera and Manny Pacquiao Mentions: Ben Jordan, Young Corbett II, Johnny Dundee, Kid Kaplan, Tony Canzoneri, Kid Chocolate, Baby Arizmendi, Chalky Wright, Howard Winstone, Alexis Arguello, Danny Lopez, Juan LaPorte, Jeff Fenech, Marcos Villasana, Tom Johnson, Kevin Kelley, Eloy Rojas, Manuel Medina, Wilfred Vazquez, Erik Morales, Juan Manuel Marquez and Chris John.
I always think of him as a 130lber, but he was an NBA Featherweight Champ in 27-28, so you are right he deserves a mention, an honourable one. I did the list a few years back, to rank Naseem post Barrera; after further research I am very high on Johnny Dundee at the moment, but I do not know if that is a flavour of the month thing and if not, he should be rated at 130.
It's very hard for me to be objective about Sanchez. Little Red is #2 on my list of personal all time favorites, and Sal beat Danny twice when I believe Danny was pretty close to his peak. Naturally I rate Sanchez just below God, but obviously, that's a bit biased.