8500 Omega's are my most consistently accurate - I timed my older tritium 16610 sub to within a couple of seconds over 2 or 3 months - but I seriously doubt it was a consistent loss or gain ;)
the DSSD is around 2 secs a day - which is more than good enough.
The 2824 movement is a good sturdy workhorse and capable of very good accuracy in COSC terms but it is not usually a 1 sec a day performer.