super curious/amused by the shifter setup
I think it's true the 7 pieces had a longer spliney piece but you can still make 7 fit on the shorter ones. you just need the thin plates. like usually each set had one thinner clutch plate (2 @ 2.3, 1 @ 1.7) and you use all three of the thinner ones - but yea requires some digging or someone with a pile of sachs clutch sets.
then you can ditch the outer alignment washer from your manual clutch set or the thick outer shims on the automatics. Then it lines up pretty well.
with the 9 pc ubers it was hard to even fit in the clutch bell lengthwise
The setscrew doesn't help much except if you're spinning the nut off a lot. which used to be a big problem with sachs but I've found usually just the 2 thinner nuts locked together is totally sufficient
Maybe shimming can give you some better grip? you can add spacers under the compression spring retainer guy on the back.