Try nbg98. But you know what, the tension is also a contributing factor to the amount of power you get.
While it has to be nautral gut. I play with natural gut when i was younger, recently i got a friend in Aust. who gave me a pack of natural gut and i restring it on my apecs 900 at 21 lbs it was magical. The touch, control, speed of the shuttel, amazing! i use to play synthetic but it seem to loss the above mention. If you have play with N.G. why not do a recent review of the natural gut you play with. It will be interesting...