Bones, before you go and change that mast at at all, either you or I will have to adjust its height. I can tell by eyeballing the rigging plans that the masts are way to tall, so if you feel an absolute need to change it today (I have a final in a summer course to study for tonight), consult Titanic: The Ship Magnificent: Volume One first, as I believe the mast heights are given in there (somewhere).