Good luck with your safety. TV would be the least of my concerns. With all the crime in Mexico, and spilling into tourist areas, I can't imagine going to Mexico. If I was on a cruise ship that stopped there, I probably wouldn't go ashore.
I know, no help to you at all.
But you might try 61.5 and 72. No need for 77, but I think you'd miss 110 on the western arc. Better to have 129 though. I have no idea of signal strengths though. I assume you remember to do checkswitches. Sometimes it helps to do one with the dish disconnected, then connect and do another.