first and foremost, as a split finger shooter i always want a very loose nock to serving fit ... not even a hint of friction or 'snap' and arrows will immediately fall off and never hang on the bowstring. my nock point is always made from tied string fiber, saturated with thin cya, and the arrow nocks under the point.
for 8 strand d'02 strings i use .019" halo center serving with no other under serving or build up. for the 4 strand d'02 string i used .026" halo.
if a less loose nock fit is required, i'd add a very small whipping of flat dental floss to the nock point area, sized to fit the arrow nock, then saturated with thin cya. if the fit is too tight, the floss can be compressed or even sanded with fine emery board grit. it'll last a very very long time.
adding a build up of strands under the serving area is, imo, tougher to get a proper fit, since those strands stray as they twist into the main body of string fiber and the resulting serving thickness you require will be harder to achieve.