Just to update. I won't keep updating on the timekeeping, just if it stops working :)
The watch seems to be a steady +4s per day. I can;t see much point in checking it in all the different "resting" positions. I always out of habit put my watches face up and 4s is pretty darned good. Beats the accuracy of my 7S26B's +15s and my Technos Goldshield "60s" Franken watch. The Franken is actually quite good with a Fontainemelon movement in it averaging about 10s per day.
Time will tell (no pun intended) if this lasts the decade+ of the Seiko and the ??? years of the Franken but so far so good. Maybe I just get lucky with watches?