Hopefully, final update:
After three days, (and the initial discovery of the watch running fast), it has only changed 3 seconds over a period of three days. Well within the tolerances for a mechanical watch.
So, absent any surprises, I consider the matter closed and can recommend Mark Sirianni's work on Omega Seamaster Pro Chronometers.
Considering that Omega now charges $550 for an overhaul for this watch, the total price, even with the return, came out to well under half that cost.