My bow is about exactly 75" from nock to nock. My bow string is exactly 72" from nock to nock. The bow is a straight profile english longbow. When I string the bow, with the string that is exactly 3" shorter than the bow, the brace height is like 10". I am stumped. The only thing I can think of is because the bow has about 2" reflex in it, the back stretches out when bent and strung essentially making a longer bow, equally a shorter brace height. I have no clue. The string is a fast flight endless loop string, I haven't put any twist in it yet.
Either way I am off to go make my third string, this time about an inch shorter,...