And BTW I am working on a collaborative review of this exceptional piece, and we will delve into this further.
My fascination of "chronometers" started will Ulysse Nardin's ship chronometers. I learned how they were used to navigate the seas, and how paramount the timekeeping precision was to that need.
If you are going to print the word "CHRONOMETER" on your watch dial, it better be an accurate piece. My sample runs fast .5/seconds a day when it is worn (and I mean after a week of wearing and setting down at night it is +3.5 seconds). It is slightly faster if I wind it but don't wear it. I have never owned a "perfect" timekeeper in relation to an atomic clock, but this sample is as good as anything I have ever owned.
The stop seconds reset function is not only a great convenience, bet very appropriate on a "chronometer". Does it make the watch run more accurately? No, but it does make tracking things easier. To the question about whether it synchs the hands after setting it at 0 seconds, YES. In fact when the sub seconds are at 15 or 45 you can easily see the minute hand less than half or more than half between the marks, and of course precisely halfway between when the seconds are at 30. When the seconds hand hits 0 the minute hand is perfectly on top of a minute mark.
I always synch my hands on any watch as close as possible. With a JLC based AP Offshore I learned to center the minute hand between two marks when the seconds were at 0. Get the crown in the middle of the play and push it in so there is no jump. When the seconds hit 25-30 that minute hand has not budged a whisker. Gets back to 0 and it is pulling the minute hand around right over the next mark.
Rather easier on the Senator Chronometer
I wish all my watches had that function.