I just posted about rebuilding the wiper bushings on my 85 Diplomat. A job that is still in progress.
The 85 Diplomat has a standard bushing (Dorman) on the motor arm—it could be that bushing is specific to the J body cars..?
Maybe try to find the arms from an M body and see if they are the same length….? Those cars do not try to “park” the wipers or hide them.