RE: string hitting arm
I looked the bow up and saw that the brace height is 6 1/8. With a draw length of 29 inches your power stroke is pretty long. Thats how they get those speeds up. I had a bow years ago that was kinda like the bow you have. I had to shoot it way different than I shot my others before it. I had to rotate my elbow out in order to get it to shoot without hitting my arm. You can use an arm guard but keep and eye on the string if you do. It could get a little frazzled from hitting a more solid object.