Ok I had to try this as this is what Federer uses. I did Grandslam gut 15L mains & Luxilon Ace 18g cross, both at 60lbs on a babalot cp machine in my POG OS (Prince Origional Graphite) Just before I hit i put string savers in, as I wanted it to last. This gut main poly cross gave me about 15% more power instantly. The string had a pop sound and feel I have never felt before. My racquet felt sooo flexable. My volleys felt like I was edberg. wow ohh wow the volleys felt amazing!!!!!!!! My ground strokes were almost to hard to control. My spinn was decent, but not more spin then with full poly. My serve was booming like becker!!! I dont want to put the gut in the cross as its so dam hard to string. i like the gut in the mains, but have not tried it in the cross. I will string 5lbs tighter to 65 mains and cross. Does that sound like a good idea or with my POG oversize should I string the poly cross tighter or looser? Whatever I do i need to tighten up the string bed as I had trouble controling the power. I love the feel, but with the extra power I could not go for my shots. i hope the extra tension will help. Any ideas on the tension, cross string, or string savers??? Thanks for any help.