Wow, those might be my favorite nocks I have seen. I know what you mean about the horn nocks, sometimes they just look too big and bulbous for me, just personal preference.
These yew nocks just look so elegant, they are reminiscent of a piece on a chessboard, and I like the way the grooves come together, makes it look like a little fleur de lise icon.
This style would for sure look great made out of horn too, maybe some white horn on black horn to mimic the sapwood/heartwood.
EDIT: fixed yew nocks to horn nocks