The way my son in law showed me on installing a rope seal is trim the shim so that the rope seal ends can meet when you put the main cap back together as on the instuctions.Also just before you put the main cap on put a dab of # 2 permatix on the two ends so that the gap from having the shim is sealed.Also to much play in the rear main can cause the rope seal to leak also,it pounds the seal out of round.
Pete