I keep a spare string in my hunting license holder each season in case I inadvertantly cut the main bowstring with a broadhead. Anyway, so it' s ready to go at the proper brace, I pull one loop (A) through the other (B) beyond by about 1/2" , then fold the sides of loop (A) back down around loop (B) and give loop (B) a tug. That keeps the string from unstwisting, so if I' m careful when undoing the loops, the brace will be where it should be.

I don' t do this, but I suppose a safety pin or twisty tie would work just as well.