I believe that he used to use Augustine (that was the only good string back then), but now he uses LaBella. I've heard it from a number of sources, but if you need proof...http://stringsbymail.com/serselect.asp? ... an=LaBella
It says under the Professional series, " Labella's Professional series strings are acclaimed by concert guitarists, luthiers, and conservatory professionals. Preferred by a whole generation of great artists including: Julian Bream
, Laurindo Almeida, Sabicas, and Rey del la Torre. "
I've never tried Labella strings, but I haven't heard many good things about them from any of the guitarists I know. Give them a try and see if you like them. Everyone has different taste in strings. If you try the Labella and don't like them, I would highly suggest the high-tension Savarez Corum Basses with high-tension KF trebles (500 AJ). The new Corum set with the new high-tension Cristal Trebles (500 CJ) may be quite good as well... I have yet to try them. In my experience, nothing has come even remotely close to the Savarez Corum basses for tone quality and longevity. All of these strings are available in regular or low tension if you prefer lighter strings. I hope this was helpful!
All the best,