Thing is, the hex of the Ceriani nut does not neccesarily need to seat on the top yoke, nor should the yoke be drawn down by the nut. The sleeve nut bottoms on the sleeve that locates the steering stem in the upper bearing once the bearing is adjusted. The position of the yoke on the sleeve nut is actually dictated by non-parallelism of stanchions and steering stem, at least on triples and SF2/3. The difference is only 1.5°, but ideally there is only a single location for the top yoke where it does not induce stress in either the yoke clamps or the stanchions and all components simply slide together without applying any force (and ideally firmly clamping the headlight support tubes at the same time). Granted, the stresses may be minimal, but from an engineering POV they should be avoided. Although the set-up may seem complicated, it is engineering excellence and actually quite simple geometry.
When assembling, the yoke should not be pushed down onto the steering stem and stanchions. The steering stem is usually quite a bit off-centre in the yoke bore, making it quite difficult at times to start the nut on the thread. Rather, the stanchions should be inserted from below into the top yoke which is loosely fitted to the central sleeve nut. A sweet spot will materialise where all fits smoothly (provided there is no distortion to deal with).
I've found all manner of shimming and spacing attempts in this area, much the same as between RH fork slider and speedo drive housing. All a matter of not understanding engineering principles.
The Marzocchi system is far less sophisticated, the top nut simply jams the yoke onto the bearing adjusting nut, requires no further explanation.
piet
