The 'packing' doesn't make sense to me, but somebody might have it a tad confused, when we used to fit Holden Red engines way back then, the Holden engine had a diaphragm type clutch fitted, we used to make a spacer that sat between the clutch withdrawl sleeve (round thing that pushes on the 3 fingers) on the input shaft to lessen the distance, as the Holden clutch was not as big as the L/R type. The driven plate should be 9" (9.5" on the later diaphragm types read Series 3) the 9" clutch pressure plate have 3 different spring ratings, they are rated by the colour of the spring, Black, Yellow and Light Green, I don't know the significance of the different colours.
The spacer you mentioned could be the fixed item which is attached to the fingers of the diaphragm clutch, whereas the std S2/2A are just 3 fingers, mate I hope that makes sense, cheers Dennis

from the parts book, the std S2/2A clutch assembly on right, diaphragm types on left with

that spacer you mentioned? maybe, cheers,,.