I wrote up a 4 part steering column DIY when I rebuilt my 63 column. Rebuilding one of these columns is a rewarding project.
Link to Steering Column DIYIf the adjustment āCā shaped piece is maxed out, then perhaps the 3 small tangs in the mast jacket are missing or worn. If the tangs look ok, then adding a shim ABOVE the stop ring (above the large spring) will help. That would move the shift tube down a bit more.
This pic shows the mast jacket tangs.