It been a while since I did the work but what I recall is you calibrate the ignition switch then remove one nut and then calibrate the dimmer switch. I believe at the bottom end both switches are held down by the same nut but at the top position they share a common stud but have separate nuts.
The top stud positon goes: Column, ignition switch, nut on stud, dimmer switch, then nut.
The bottom position goes: column, igniton switch, dimmer switch, then nut.
I also checked and my 88 XJ does not have flash to pass, just low beams OR high bearms.
I had a guy advise me and you can just loosen the column attachement point closest to the driver and let the column drop a couple of inches. Leave the bracked on the column but you may want to loosen the bolts attaching the bracket to the column to aid in reassembly. You will bend yourself into some positions you have not been in for a while but it can be done with the column still in the vehicle. You will have to remove the lower dash board trim, the piece with the ash tray to do this job.
This job goes easier if you have a friend along who already done the job. I started doing it and my buddy who was there to watch jumped in and finished the job. He came by to watch and could not help himself
Also make sure you buy the right type of ignition switch for your column, different switch depending tilt or non-tilt column