My recurves are also 50 - 55lbs and the 12 strand D97 seems to be a really good combination of speed, quiet and no vibration after the shot. I've heard that at our weight we could go all the way down to 8 strands of D97 but the increase in bow noise might not make it worth wild for the extra speed. The fewer strands also means that the serving will have to be a larger diameter or have extra strands underneath to build it up for proper nock fit. If you use something other than D97 then you will have to base your strand count on the breaking strength of the string material you are using like for Dacron you might have to go with a 16 strand string to get the same strength as say a 10 strand D97 (not an exact but you get the idea). Before doing anything, make sure your bow is designed for FF and other low stretch strings so as not to damage it. If your not sure of what you need, talk to the string sponsors hear and they will guide you towards the best setup for your needs. Regards, Ken