Just spoke to our friends recently returned.. They used a Delta-like plow with good success between San Carlos and Manzinillo - plenty of scope and seriously set (1500 rpm).. this on a Passport 40. Not sure the anchor weight.
He also said they encountered all types of bottom conditions but that sand was the predominant one.
He thought your large Bruce would serve you well too most places.
btw what boat are you on?
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)