So if I am reading this correctly, you have shot "a lot" for the last 2 years, and shoot directly off the string with a release. If it were me, I'd definitely get a new string before going any further, but that's me. From what I see on here, you probably can't get a better string than those made by your fellow Canadian gibblet. You might want to contact him for advice.

BTW, if you shoot with full body armor and a helmet with a strong face shield, you should be fine if a string lets go at full draw.[8D] If you don't take these precautions, then like gibblet said, you don't want a string to break at full draw, and neither does your bow.