Originally Posted by The Meat
Why in the crosses???? A shaped poly should be installed in the mains for the maximum benefit.
Roger Federer does the same thing. Wilson gut in the mains LXN rough in the crosses. The mains are the primary string for power, control and feel. Some texture on the crosses ads more bite on the ball and poly strings in the cross allow for less movement on the mains, and tame the power of gut.
EDIT: Andy Murray on the other hand seems to like poly mains and gut crosses. There isn't really a right or wrong way to each his / her own.