There are usually a lot of twists near the string loops, and it would definitely threaten the integrity of the string if those were untwisted. Usually these tight twists extend 7-8 twists past the twists that are actually needed to hold the loop together. The twists in the middle of the string can be further apart. My rule of thumb is to leave at least one twist every two inches in the middle of the string, so the tight twists near the string loops don't start to untwist.
Usually, a new string that has not been pre-stretched will stretch enough during the first hundred or so shots to require a dozen or so more twists in the string. So you might have to start off a little over the recommended brace height at first, and let it settle in.