go to current tennis mag, I think page 75 has a close up on face shot of his racqet head last year at Wimbledon.
Notice on the PWS part of the frame, 3&9 oclock, that he has 4 crosses coming out, a stock tour 90 has 5 strings coming out form this same area, yet both Rog's and the stock verson are 16x19 patterns, so Rog has a more open pattern in th emiddle.
A PS 85 has 4 strings coming out of this zone eventhough the PSW is shorter on the 85 frame, the spacing is still wider than the stock tour 90.
Also the tour 90 stock is missing some feel and for 5" bigger has a squirly sweetspot. Looks like Rog picked up on this and the string spacing has something to do with it. Crappy hyper carbon effect as well. I wouldn't be surprised if his molds do not have hyper carbon and just use the holy grail comp of 80/20.