Dennis: Ironic that you bring that fly up. I fish Campeche 2-3 times a year, and do so with the "originator" of that fly, Raul Castaneda. The baby poons down there love it, especially the ones on the clear mangrove edges or a bit off shore. The brighter yellows and reds seem to work best up the creeks or in wind-stained water. I'm headed back down in 5 weeks!
From what I can tell, the splayed hackle version has been around a long time. Joe Brooks, Sea Ducer, Etc. Here is what was supposedly Raul's original "campeche" version. He loves flash, flashabou, etc. It has rabbit, but is harder to cast.
Brooks Tarpon Fly:
All pretty much the same fly. The tarpon don't care what we call it!