I have been playing consistent tennis for about 30 yrs now (45 yo). I am at a 4.5 level & hit massive spin both sides. To avoid spending a lot of money & time with stringjobs I have been playing with kevlar hybrid, or poly. I recently bought into the RPM hype about being soft for a poly & generating good spin. I do feel the softness, but it is still killing my arm, so much so, that it is reducing the number of days in a week that I can play. I now need at least 2 days of rest after playing.... sux. I have always strung a little high (rpm @ 59 lbs); furthermore, I do not even think rpm is anything special in the spin dept., I think a kevlar blend provides more spin. Anyhoo, I need to make a change. If anyone here has been down this road, please recommend to me a soft (easy on the arm) string, eg . nxt is great, but I snap it within 3 hrs. I want something that is soft & produces major spin. Feel free to recommend tension changes as well.