I've gone through several of them in my shop--great bows, great price.
The arm slap is generally caused by one of two things: if you are "double jointed", just get an arm guard and be done with it. An arm guard is a good idea anyway, as it helps protect you if you have a damaged arrow that breaks on release (had it happen to me once), and in cooler weather it keeps your sleeve out of the way.
It could also be your form. Most everyone has a tendency to lock their elbow when shooting, which basically points it straight down (toward the ground). Turn your elbow out, at a 90 degree angle, and it should get your forearm out of the way. This works regardless of the amount of cant. Practice by making a fist and putting your knuckles flat against the wall, then rotate your elbow out. You can do this without moving the angle of your fist--do the same with a bow in your hand.
Chad