The best way to repair those would be to TIG weld them, you are correct. I am currently in the process of doing just that. I have another video showing some catastrophic damage to the primary side case. I purchased a TIG welder and taught myself how to use it. I will be posting footage of those repairs soon.
I took an old friction disc and steel disc and bolted them together as to replicate Harley part; 97175-55 "Clutch Lock Plate" I then took some 1-1/4 flat stock and 11/16 tube stock to replicate Harley part; 97200-55 "Sprocket Locking Link" You can reference these tools on page 4T-2 in your service manual. I hope I answered your question. I appoligize for the delay in answering you, your question went to my "Spam" folder.
"Locking Tool"; The plates are made from 1-1/4x1/8in. flate stock cut to 3-1/2in. long. The spacers are 3/4in. round stock cut to 1-1/2in. long and I am using 1/2in. grade 8 bolts 2-1/2in.long. The holes are 1/2in.drilled 3/4in. on center from each end. The "Clutch Basket Lock" is made by simply bolting together 1 old friction disc and 1 old clutch plate. The two bolted together when placed into the clutch basket locks the outer basket to the inner clutch hub. When using the two tools together you immobilize the entire primary drive as to loose or tighten the PTO nut and/or the clutch hub bolt.
The plates are made from 1-1/4x1/8in. flate stock cut to 3-1/2in. long. The spacers are 3/4in. round stock cut to 1-1/2in. long and I am using 1/2in. grade 8 bolts 2-1/2in.long. The holes are 1/2in.drilled 3/4in. on center from each end.
