Living in the Past
SILVER Star
No steering expert but think caster can be effected by the springs. As the springs flatten out with the fixed pin at the back the shackle angle will change effecting the caster. Wedges, arcing or new springs or different shackles could correct this. Camber I have no idea. Personally I would correct the caster and see with alignment how it steers. I would also watch for wear patterns on tires.