Here ya go, Pete:—

Uno!!
Dos!
Tres!
Cuatro!

In "Cuatro" there is a forum. I put "tuning" in the dialog box and came up with quite a number of questions from aficianados and aspiring guitars about tuning. In most cases of "Does so-and-so use a special tuning on such-and-such? It sounds different," the answer comes back, "He has the cejilla on the third fret, but he uses standard tuning." There's one person who says something about using a dropped D tuning for a Farruca, but this strikes me as bogus. The Farruca uses the Am scale and chord set, with the E chord being quite prominent, and the bass falsetas spend a lot of time on the 5th and 6th strings, so I have serious doubts about this. Apparently dropped D is used from time to time, but it isn't common, and it's more an idiosyncrasy of a particular guitarist than it is common practice.   

Don Firth