Thought I would start a "club" for all us natural gut / poly hybrid users to compare notes. I am playing with a Becker London with Head Natural gut mains and am testing copoly crosses now. So far I have tried: 1) PF Black Venom - very nice. soft and low powered 2) Volkl V-Pro - also soft and a little more pop I think the ideal cross for nat gut mains is a round, smooth poly that will slide easily along the gut. Also the round shape will not wear out the gut too fast.