The buckets move in a confined arc, so if you are at the limit of adjustment when up on the limit switch, then the bar needs rotating in relation to the gear piece (cut and weld). I assume you have plenty of adjustment on the lower limit switch (closed position stop), so you can adjust the close position back with that. It's really about getting the gear drive centered on the motor drive when the buckets are halfway open and then you'll have some adjustment in the open and closed positions. Of course you should also check the headlight beam is correct, but that is adjustable at the sealed beam under the trim with 3 screws.
For adjustment of the bucket position in the opening, the buckets are bolted to a bracket on the rod and can be accessed from inside the fender to adjust side to side or front to back slightly. If one bucket is slightly out in relation to the other you can shim a little between the bucket and bracket as well.