3189t,
The late Robb White's son, Wes, has built a good-sized proa with a crab claw
rig. He has been testing it and writing up some of the results over the past year or two. His reports appear in various issues of Messing About in Boats. Wes sometimes lurks over on the builder's forum at Wooden Boat, so you may be able to contact him directly there. I can't remember what his on-line "handle" is, but his father went by "Old Bingey" so if you search his name you might find a discussion of the proa in which Wes participated. Good luck to you.