Thanks.
One of the highlights from my Bluegrass fandom was seeing the Country Gentlemen, with Bill and later on without, warming up in the parking lot of the Whippoorwill Festival in Warrenton VA, as in the Matterhorn clip above. He was a master of Scruggs-style banjo.
After not hearing about him for some time after he joined the U.S. Navy I was delighted to hear him playing better than ever on Tony Rice's "Tony Rice Plays and Sings Bluegrass", one of the best BG albums ever recorded, IMO.