Is the twist border too big or too small? First, count your pattern repeats to make sure that you have them all (or if you have any extra). You might be able to add or remove a repeat.
OR
If it's too big, just add another plain border to make it fit. If it's too small, the only way I can see is add another repeat of the twist, to make the twist border longer, then add another border to the quilt to make the revised twist fit.