This is so very well recorded. Great production values as well as excellent playing.  That's my old Cammeyer Vibrante Royal banjo.  It looks like it has the same strings I put on it when I sold it to Bill.  A real gut string for the middle G and a "D Series"  copper-wound lute string (copper wound over a thin metal core which is wrapped in nylgut filaments),both from Aquila. These are the best sounding 3rd and 4th strings I've found for zither-banjos.  Nylon or Nylgut is also good for string 3.