If memory serves, Murray has a REALLY high stamina rating...that is a definite factor. Also, I played with 58 fatigue, I don't see much difference between 50 and 58 with regards to subs. I did start to see more of a difference at 60 though.
If you're dead-set on using acc clock, I always found that 12-13 minutes with 18 second runoff always gave me that 120-130 play count we want (just like 9 minutes with no acc clock does).
Enjoy...