Poly in the crosses ala Federer, helps tame the power of the Gut and allows the gut mains to slide and snap back for more spin. I am a little suprised she is using a shaped poly in the crosses as opposed to a round smooth poly, but she obviously prefers Tour Bite.
Using Gut in the crosses, IMO, would be a waste. May as well just use a synthetic or multi.
Racquets:Babolat Aero Storm Tour GT, Head IG Radical Pro, Pacific XForce Pro
Machine: Prince 3000