He played with a PS 6.0 85, from St. Vincent. I actually met him this year at the Nasdaq, and took a picture with him. He actually allowed me to look at his racquets and speak to him about his use of these (PS 6.0) racquets- 2 Wilson 6.0 85's, both from St. Vincent.
The picture I took with him has both racquets.
Awesome player, one of my favorites.
Roger Federer Pro Staff 97 Play test video