I played with it at 54.. just because I always strung my polys high and it still played well. But I admit It developed better pocketing and play-ability imo after some break in/tension drop. Went 57 and it was gross, cut it straight out. I think im gonna drop down to 54 mains and 52 crosses next job though.
Head Extreme IG Pro: Klip 18g Gut Mains at 54 & Prince Beast XP at 50
Head Extreme Microgel MP: Lux Adrenaline at 56