Jolly, any particular reason why you string at 70 pounds?
Just wondering if it does something for you that a lower tension doesn't.
Well when I played my N90s I strung at 58.
Then I switched to the J90, and started at 58-60. And was hitting everything long, and so adjusted, never assumed that I would end up at 70 in my wildest dreams.
With the looser tension, I have to hit more top, and put more arc in my ball than I care to in order to keep it in. So I raised the tension until I was hitting the ball at a trajectory that I was happy with. 68 fresh off the machine was perfect, so I string all my frames at 70 and don't play with them for at least 3 days after they come off the machine and go through the initial tension loss.
Now with the 70 I can blast flat balls corner to corner, but retain the ability to hit heavy top, or just a heavy deep rally ball.
Higher than 70 I would have to hit flatter than I want to get the ball through the court, and lower I would have to hit more top than I wanted.
Basically I looked at my style of play, and thought of what would be ideal to me. And adjusted to the tension that best allowed me to hit that way.
J