B50 or B55 about 60" long should do the trick. You might have to twist it a bit to find your bows sweet spot.
General consensus is to stay with a string that has a bit of give in it at the shot so it won't cut the tips off of the bow. Someone will be along directly and tell you something different about that. Unless you are trying to get everything that you can out of the bow, the old rayon fat strings are cheap and safe. They are slower but I am one of the guys that enjoys seeing a bit of arc in archery. I buy the stuff for five or six dollars a spool and build strings for about a dollar apiece.