My 2003 Bowtechs had the same problem with Easton super nocks, the current method string makers are using is to lay the serving material full lenght under the serving and then serve over it which builds the string up a litlle causing a tight fit. On my two bows you could hang the weight of the bow and then some from the nock without it disconnecting. I would reserve using BCY #62 or 62XS in the .018 size if using a loop or .019 BCY Halo if using fingers.
Good Luck
BD