Anyone tried the 6 strand SBD string ?

[Burnsie]

I like the 6 strand Ultra from a performance and quietness standpoint,  but I have had trouble getting the darn things to quit stretching.  I currently have one I had built for a 60" recurve,  put it on and it was fine,  got it shot in and things were looking good.  The bow sat on the rack strung for a few months,  and when I went to use it, I could tell right away by looking at it that the brace height was way low.  I twisted it up as much as I dared without getting it all kinked up and it was still too low.  At that point I decided to untwist it as far as I could and put it on my 62' bow.  That string has now settled into about 3/8" higher brace height than I usually shoot on the bow,  but it is super quiet and really zips an arrow.  I'm going to run with it like that see what happens.
As a side note,  one of the few negatives I see with a real skinny string is that you have a pretty narrow margin for error with the length, when it is built. When it is that skinny with few strands you hardly gain or loose any length by twisting or untwisting the string.  You need to be pretty darn close with length to begin with.