20mm cannon shell cans dwarf Knuckle/Pan/Shovel FL rear fenders. You may not want to run them on a mini-bike like the LS650/S40.
Even standard sized Saddleman Desperado semi rigid bags are too large for a stone stock Savage, let alone a cut down. I use them on my 98, which runs an FL solid rear fender...
...yes, the chrome sidemount headlight adapter is the rear fender primary mount.
... it is very easy to go overboard on your bag size, even wiih the full rear fender, this is about the max you want to run. And yes, the fishtail pipe IS the secondary rear fender mount, via a VN800 rear reflector bracket.
Solo seat is long gone, it sucked. Dixie brand from Jireh or Fog Hollow, or Canyon Run (same company, different brothers running different divisions, kind of like Lowes and Home Depot)...