Peppe has made two steps forward and one step backwards as he came across a nuisance with the clutch that required a little extra thought to diagnose.
Basically, though everything appeared to be in order and was, in fact, correctly assembled, the pushrod actuating mechanism (which uses three ball bearings sandwiched between two small metal plates in order to expand as it rotates) was not able to lift the clutch pressure plate on the opposite side, at the clutch basket. Instead, under the strain, the mechanism was "camming out" with a nauseating crunch. Long story short, it turned out to be a matter of very fine adjustment at all points, due to the fact that modern friction plates are thicker than original specs, therefore eating up much of the usable length of the normal pushrod adjuster (the one that sits in the centre of the pressure plate).
It all works as it should now, and with the first signs of wear, further adjustment will compensate and bring the situation back within normal parameters.
Still, an unexpected delay. Will it still make its scheduled test ride tomorrow night?