It always seems a shame that it's very often pot luck on getting a watch that's close to its potential as a timekeeper. As an accuracy freek (although slightly reformed), poor regulation is still a pet peeve of mine. For example, it seems ridiculous that Omega bother to provide the co-axial movement with excellent potential for long term stability, but then don't bother to regulate it remotely well.
I'm not going to talk about adjustments for a watchmaker to consider just the brute force regulator shove..... Anyway, so to the handy tip. If you're not going to wear the watch in normal use, the best position to leave the watch in for a while (or if you're lucky enough to have access to a 'Witschi' you can see instantly) to see how your changes are doing is as follows:
8 o'clock high (8H) lent back (dial up) 30 degrees.
This has been found to be the best representation of position a watch finds itself in most of the time in normal use.
Popping the hood and tweaking the 321 in my CK 2998-6.
What an incredible movement in the flesh, - must fit a display back soon....
Oh, and try not to do it wearing a fluffy jumper.