Can anyone tell me which Easton press-in nock (Super, 3D Super, X, S, G, H ) has the largest groove for a softer fit on a larger diameter string.

I have found the Easton large groove G-nocks and Easton 3D Super nocks,fit nice on finished string diameter around .108 to .110.The 3D Super nocks different and have a larger groove the the regular Super nocks.

Thanks JRY, do you know if the large G nocks will fit in uni bushings used for the Super nocks?

No G-nocks require arrows with G-bushings,they have a .166 ID of the bushing.They are a direct fit with the new Easton Injexion arrows.The 3D Super and reg. Super nocks fit a uni-bushing with a .246 ID.Which is the same as most standard 5/16" carbons like GT,Beman ICS and other with that same ID.And all aluminum arrows 20XX and larger that have a uni-bushing.You can get G-bushing for for use in 5/16" carbon arrows and a few others at 3Rivers.