[embee]

Of course the manual is correct, just that in practice if you let the worm lever go right to the stop (i.e. cable fully slack), and then back the centre screw off about 1/4 turn and nip the locknut, you'll find that the take up will be at more or less what the manual says (just shy of a right angle).

In theory the manual method is to get the clutch operating range (pushrod actually moving the clutch pack) equally around 90deg between cable and lever where it will be working at its best.

As thedonal says, the lower cable adjuster takes up most of the slack, and leave yourself fine adjustment at the handlebar end so you can fiddle with it easily.

Common sense says check the actuation once it's all adjusted and see that the lever works around 90deg, before refitting the cover. Once you've done it a couple of times it'll all make sense.