I've decided to try and get away from Problend in a 78 stiffness racket, mostly because as I've gotten more tennis-fit and am swinging harder, when I mis-hit it is VERY jarring. I've gone to the opposite end of the spectrum and have tried NXT OS, and it has been pretty much exactly the feel I don't like. It lost quite a bit of tension and now is very springy, mushy, and trampoline-like. I can still play with it, but it is strongly not my preference. I want to try and replicate the feel of Problend but end up with a stringbed that isn't so jarring when I hit off-center. From the USRSA site, I've read that the Problend results in a stringbed stiffness of 981 lbs/in, I'm assuming at the standard reference tension for measuring this. If I choose a string with a stringbed stiffness of, say, 500 lbs/in, is there some rule of thumb or formula that I can use to calculate what tension will result in a stringbed stiffness of 700 lbs/in, or 900 lbs/in? Does this rule of thumb or formula apply to all strings or only some strings since their stiffness doesn't increase linearly with tension as a whole? Thanks.