Before I started to dissasemble the engine, I bought a cheap chinese copy of that fancy electrical Bosch thingy off fleabay.
Showed up to be a rather solid and powerful tool, having just the right torque range for primary sprocket and flywheel nut. Has just an on/off switch, so the handling is less immediate, but still close to an air gun. Used it on the flywheel puller as well, worked a treat. Same for assembly. No fancy tools or bodges required for locking the crank. Just whacked the sprocket nut up, until it stopped moving any further.
Flywheel looks a bit more tricky, as there seems some risk to crack the hub by pulling it to far on the cone.
Nicely enough, the clever Breganze folks added a figure to the 3C manual, showing the required distance between flywheel face and seal face cover, 36,5mm +/-0,15mm. That way it took 2 or 3 sequences of rattle and measure, job done after 30 seconds.
In the meantime, this cheapo electrical rattle gun made work so much easier on many more occasions, it has become definitely my personal best 44 euros ever spent on a tool.