[Lynn Eades]

Richard when the carrier is on its tracks with the weight down. swings the hull easily from side to side. the rollers should have a 0.001" clearance. What Rob was referring to was that a badly profiled cam plate will not maintain this clearence through its travel.
The self aligning bearing goes in the bottom of the steering column, not the cam plate. It seems it wasn't important to use one, as many were fitted with annular grooved ball races (ordinary brg) in service.
Be aware that the spline at the steering box is indexed to the column, and needs to be correctly timed. The Canadian MkI* book gives a very good description of how to set it all up.