Any bar that has all 4 lines the same length will work on a B6.
However it might change the kites flying characteristics a little if the Y is positioned far from the original position found on a B6 bar.
How would it affect the characteristics? I went for a Slingshot bar instead of the F-One and found the back lines to be very slack. I wanted to try my old Bandit 3 bar to see if it improved. If it did, I might have to go back and change my two new Slingshot bars for F-One bars. I went for the Slingshot bar as I got a much better deal, which when bars cost what they do know, made a difference.