I have always used 12 strands of B50 for bows over 50# for long term durability and a thickness to ensure a tight nock bite.
I did some chronograph with my bow with both 10 and 12 strand strings to be sure of speed. I did not find a significant difference and was surprised to to see about 10 fps varince both ways (10 shots with each string - different arrows) The arrows were aluminum which I assumed to be the same weight. I used a thre finger under release.
Have you guys seen a perceptible advantage to a 10 strand vs. 12 strand?
OBTW, I use 4 extras strands in the loops to insure longevity.