Probably you belong to those who like multi-filament strings (much) more than poly. (i am also one of them) If so, it's wasting time trying to find a poly string to beat yr fav NXT 16. you should look the other way, ie. better multi like X-one Biphase or Natural Guts.
btw, just be nosy, what racket you use to string that low tension ?? 'cos sometimes stringing too loose may reduce the string's life due to sawing effect.