RE: adjusting brace height
You have to fiddle with both. Twisting the string to shorten your axle to axle and raise the brace height will shorten your draw length and mess up your cam rotation. So you have to twist the cables to get your draw length back and readjust cam rotation. Once you get close, then you take out or add a few twists on the string and/or cables to get things the way you want.
It's not as complicated as it sounds, but it does take a few tries and a little patience sometimes.