Oh man, sorry to hear that at the end.[emoji17]
It was easy for me modding all my switches Z52, Z57, Z41, SW02, Z58...
Too much of a generalization here -- every switch disassembly is different
Z52: should be easy as you've mentioned, but truth is, YMMV;
Z57/61/68: mostly easy, but the golden rule is to apply torque to the retainer ring slowly, and with an appropriate pair of nose pliers. Needle nose pliers (I mean the very sharp one) won't work and will 90+% scratch up the retainer ring bad (I've been there). For Z57/61 disassembly I also have a custom key made just for that (won't work on the Z68 due to shroud height);
SW02/Z48/Z49: wouldn't even think about it. It's doable, but again requires real torquing tools. I've sold my SW02 and Z48 beczu I know I wouldn't be able to service them myself;
Z58/59: depends on batch. Earlier batches were quite easy to open -- just get enough grip on the top cover and turn it. No special hex key necessary (but again YMMV). Newer batches however are a real PIA as the entire construction of the host has changed so the host is not a top+bottom piece combo anymore. Have never tried the newer batches so no further comment;
Z41: have done this all the time, but again, different procedure depending on unit
For some units, gripping the inner core and rotate it a few times, it (and the rivet) would gradually unscrew and come out. The subsequent Delrin retainer ring is also not hard to remove but in extreme cases, heating and freezing trick is needed.
If however the core doesn't get loose after a few spins, force may be applied to try to yank it out, but will definitely inflict more tool damage on the surface. Also takes more time than necessary. So depending on batch/unit I sometimes work from the boot side, ie. peel out the (fully lubricated) rubber boot carefully then use a pick to hammer the guts out. It's easy, but the heating and freezing trick sometimes still applies when removing the retainer ring.
