That's a bit trickier - depends on a lot of things. I'd also aim for a lot of twists in the string - I aim for around one twist per inch. That's more than most makers would allow for, so specify that when you are getting a string made.
I've had my limbs for about two weeks now - but haven't had the chance to shoot them much yet. However I did discover the 64.5" string was too short. Sid recommended a 65" flemish twist which definately works for getting down to the requiered brace height (6.5-7").
My set up is a 25" Uukha riser with short Hex 7.2s at 36lbs. So far every arrow I've tried makes a fearsome racket. I've tried ACGs in 540/610 and 670 all with 120gn piles. Barsehaft 540s and 610s are showing as rediculously stiff - the 670s are slightly better. But I didn't like the sound the bow was making so stopped shooting. Will drop the nock point and get some less-tight nocks and see what that does. Any thoughts?