My thought is that although the string will stretch some, it’s not going to stretch that much. I usually get about 3/8" brace height stretch. I would order a longer string and twist it up some. The longer string will give more adjustment latitude, both lower and higher brace height for better tuning. With a 56” AMO bow (I'm assuming recurve at that length), the accepted string length would be 4” shorter, 52”