When adjusting brace height, do you just twist one end of the string or both? If just one end, then which one? If both, you twist the top end one way and the bottom end the opposite, correct? I've always just taking the top one and twisted. What's the correct way of adjusting the height? Thanks for all the information.

i twist from the bottom just because that's the easiest way.  You can twist from the top or bottom...doesn't matter.

brace height thread  

Here's a previous thread on the subject.