I use natural gut on the mains and multis/synthetics on the crosses. I also put a lot (52) of babolat string savers in the sweetspot. I noticed that the crosses are breaking faster than the mains. I am on my 3rd cross but still using the same mains: i only re-string the crosses because the mains (natural gut) is still in excellent condition. When i re-string just the crosses, i do not see any frame warping or frame cracking that many people on this site claim happen to them. Question: I string my racket below 50lbs for the mains and lower for the crosses. Have you personally experience any problem with the racket when re-stringing just the crosses or you just heard about it??