Here's your advice- Learn to say "Uno Mas Cervesa, Por Favor" !

Manz is way down South on the Pacific side right? I believe that's where my Bro-inlaw went a number of years back. Paid a kid $25 on the beach to go out in his Panga. Caught a real nice sailfish!
Enjoy (you dog -free is a very good price), hope you get some more specific advice from the Salties.
PS- I would not worry about setting up boats in advance unless it's spring break or some tourney is happening. I would rather walk the docks, watch the boats come in and talk to the crew than set up a Mexican Charter blind from here. Besides, what better way to spend a couple hours the first day or two. The boats usually come back in from 2-3 in the afternoon.