You don’t have to (and you can’t) twist headshell-integrated cartridges like SPU and FR7f type, they are fixed with correct overhang and if you will check them with Dr.Feickert protractor they’re spot on (with one of 3 possible methods) if your PS distance is correct.
If you have conventional cartridge screwed to the headshell without slots but with treated holes then it’s nice to have overhang adjustment on the headshell (like AT Technihard, Stax and others).
Even if there are no lots there are at least 2-3 pairs of fixed treated holes for mounting screws and this is how you can adjust overhang altering position of the cartridge, but you can;t twist it. This is indeed not ideal if your cantilever is off-centered.
Headshell with slots, azimuth and overhand adjustment will give you everything, but it is not rigid as the shell without those options.
If you have conventional cartridge screwed to the headshell without slots but with treated holes then it’s nice to have overhang adjustment on the headshell (like AT Technihard, Stax and others).
Even if there are no lots there are at least 2-3 pairs of fixed treated holes for mounting screws and this is how you can adjust overhang altering position of the cartridge, but you can;t twist it. This is indeed not ideal if your cantilever is off-centered.
Headshell with slots, azimuth and overhand adjustment will give you everything, but it is not rigid as the shell without those options.