Rick: The Radiola Guy's website shows a listing for a Simpson 335 schematic with supplimental tube data (copy for $10) if that's any help. Go to: http://www.radiolaguy.com/manuals%20Test%20Equipment.htm for more info. Also, the Boat Anchor website has the manual and tube data info for their model 305 which may be the same or similar as their 335. Check out: http://bama.sbc.edu/simpson.htm.
Good luck,
Steve