I am looking for thin and durable strings like NBG 98, so I can get the high tension feel at lower lbs (less stress to the frame). (need to get 2 lbs lower to keep the warranty) Even 0.68 mm Strings are OK when they are durable. I tried BG80, BG66 UM, BG80 P, and LN N30 but they all broke too fast for me. The only on of the thinner strings which was OK for me is the NBG 98.
You've not explained why you don't just use NBG98 ?? I am currently using it for similar reasons to you - higher tension breaks too easily....
I use nbg 98, but often the stringers at the tournament or at the shop have not that string, and i am currently out of NBG 98 strings so am looking for possible alternatives.
Ashaway Zymax 65 (ZM65) is a good choice. they are harder to find than Yonex. though i was told that it is more popular in Europe.
zymax and nbg range is a good choice... but the question tbh is kind of like asking for a Sports car that runs slow >.<
this!! i'm also looking for a cheap, thin, durable, repulsive yet hard and rough string. for me, the best string is BG80. it's thin enough and plays really well. durability: well... (who cares...).