Make a burr on one side then flip the burr to the other as you progress up in grits. Mount the belt sander so you can use your body motion to pull it through rather than just your arms. Also move in a faster motion as the grits increase due to heat build up, start slow on cheaper blades till you get a "feel" otherwise it will be real easy to generate to much heat at the tip ... The angle is emtirly
up to you, a slack belt will make a nice convex that is easy to maintain