So, what are you planning on putting in there? If you have gut, I'd go w/ 54lb gut mains & 50-52lb poly crosses, depending on the poly. That 4G you had in your racquet felt nice. Maybe 50lb 4G crosses. If all poly, then no more than 52lbs. Your probably better w/ 50 in a full poly. Of course, thats assuming your machine & mine are putting out the same numbers.