As I said Piet, I've no practical experience.Paul,
The splines of the centre journal allow absolutely no leeway for any adjustment, unless you re-assemble the crank incorrectly on purpose. If the splines are damaged upon re-assembly, chances are that the webs will work loose in a very short time, resulting in a horrible mess. The bolt that holds it all together is dependant on the splines to keep the plot in line.
You'd be surprised at how bent and wobbly most cranks are. Wear at the mains allow the cranks to throw their weight around, resulting in "they're all like that, Sir" vibes. A sure tell-tale is pitting on the outrigger bearing race or even a loose race, I find up to 0.5mm (instead of `+/-0.05mm max) run-out here. The difference you felt results solely from new bearings and reducing run-out to a minimum. Even the factory balancing was well inside the ball park.
piet
I distinctly remember Phil mentioning 4° leeway either side of spot on.
I well understand that the centre piece being forced into the webs, that sets it for eternity so don't understand Phils 4°.
Paul