Got her back yesterday - definitely feels more compliant and supple with the Belray 5w High Performance fork oil. Adjusted the compression and rebound a just half-turn stiffer to compensate for the new oil, and seems very good for now. Kept the stock Marzocchi springs, and still seems fine for my 190lbs. I set up the sag and pre-load 5 years ago when i got the bike and have not changed it. Thanks for all the help and input everyone.
Incidentally, had a great time talking with Roland at The Spare Parts Co in Philly about everything Guzzi. They've been open since '81, and knew Dr. John Wittner well.