OK here is my input on this. Brass knocking points were OK for me but they tended to wear out my tab. For this reason alone I removed them and used serving material. I favoured a light coat of thin modeling Dope. It shrinks as it dries. The nocking point will not come undone or fluff up either. But it won't come off either.

When I removed the brass nocks I did notice a change in tune. The extra string speed made the arrow behave weaker. Just like adding more poundage to the bow. But as long as the spine of the arrow is pretty good anyway a twiddle with the preassure button will sort it. Your bow will need bare shaft tuning the get this right.

I suspect other influences on the arrow, such as the way you loose, and other form considerations will have a more dramatic affect than nock point weight. But little changes do add up.

Rich