Strongly suggest that you find a copy of "The Matamoros Trade" by James W. Daddysman, Newark: Univ of Delaware Press, 1984. Quintero comes out very well in this volume and was obviously a key person in the border trade. His advice cleared up one major obstacle and then Richmond stupidly countermanded him. He seems to have taken some real personal risks, especially due to the turbulent situation in Mexico at the time. Hope you find a lot on him.