The point being there's too much emphasis on particular strings, and not enough emphasis on player developement, technique, and strength.
I use Mfil and Aero 200's, 18x20's, strung with 15 gauge cheapo nylon.
Right up to 5.5 levels, nobody says my shots lack spin, speed, depth, or pace. They say my fitness sucks, I can't cover alley to alley, and I'm blind.
They even try my rackets for a few hits. They say it's OK, surprisingly. That includes 2 current Div1 singles players, and and least 4 other former Div1 singles players.
It's not the strings, it's not the racket, it's the player who makes the difference.
Note.... all five guys use different rackets, strings, and tensions.
Respectfully disagree. Strings do make a difference. The difference between a kick serve that hits on the service line and the one that hits 2" long is not many revolutions. Same is true for pretty much every shot.
It's great that you can hit the strokes you want with 15 gauge nylon. I know from experience that I can't produce the kind of spin I want with 16 gauge synthetic gut in my M-Fil 200 18x20s, so I play with 17 gauge strings that do it better.
I suspect we are looking for different experiences on the tennis court, as are all 5 guys you mentioned. If there were a holy grail that worked for everyone, it'd be pretty boring on this board.
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Back to the OP. If you want to reduce the power of the frame and get more spin because you swing for the fences on every ball and want them in play, I'd play around with a poly or poly/synthetic hybrid. On this board, there are many popular poly's for doing just that:
I've tried:
Topspin Cyber Flash 1.25 (playing this one right now, love-hate relationship but have gotten comments from the best players I play regarding increased spin rates from fresh string jobs - and I tend to keep the ball in play then too - you won't break it, but will need to cut it out at 10-15 hours of play to avoid damaging your arm and being frustrated when balls start sailing)
Signum Pro Poly Plasma 1.23 (like this string, more muted than Cyber Flash, some say softer, maintains tension better, but it's a serious pain to string with. Warning: I think it's brittle and am scared of getting near it because I've had several frame breaks on relatively new string jobs with it and had it break on the stringer. It is popular, so obviously it doesn't happen to everyone)
I haven't tried, but am considering:
MSV Focus Hex 1.18
Signum Pro Poly Plasma Pure 1.23 (supposed to be softer than regular, and is nicer to look at because it's not orange)
Pro Supex Big Ace (gets a lot of press on this board - may try it)
Also pretty much every other Topspin Cyber string, since I like Cyber Flash (and am going to try the 1.20 to see if I can generate even more spin).
Good luck. Try a few and decide if you like the combination. As someone who started out using exclusively PSGO, I vacillate between synthetic gut, hybrid, and full poly stringing. So far, my arm doesn't hate me for it, but my racquets are pretty heavy and flexible.