I recomend two nock points, one above and one below for three under, if I nock my arrow above the nock the extreme FOC I hunt with slides the arrow nock up, but a good point that just moving the arrow above will raise the nock height as is needed for me when switching from split to three under.
Three under was noisier for me when I first switched until I started with a deep hook, then the release got very smooth and noticeably quieter.
It takes a while for it to feel natural after shooting split for a long time.