Whoa there... Jerry Garcia's best known guitars were built by Doug Irwin, not Alembic. Irwin had worked at Alembic and his guitars are clearly influenced by Alembic's designs, but Rosebud, Wolf, and Tiger aren't Alembic products. Alembic's Tribute guitar is influenced by the design of Tiger. Garcia didn't play a lot of electrics, but played SGs, Travis Beans, and a custom-built Cripe guitar which was influenced by the Irwins as well.
Phil Lesh did play Alembic for many years, and the there are many, many close ties between Alembic and the Grateful Dead including The Wall of Sound, and Ron Wickersham working magic in the Dead's studios.
One Alembic guitarist that was very prominent was Carlos Alomar who played a beautiful Series I guitar behind David Bowie for many years and many albums.