nock overlay orientation

[lleroy]

When making nock overlays from wood, would there be an advantage in one orientation over another?

[M2A]

I'd flip those 90 degrees and use the rift or quarter sawn side for the string to seat on. I'd be concerned with the rings getting pulled apart by the string in your examples. I have done overlays like you have pictured with no problem before I put any thought into it so maybe thats no big deal, and black ebony can be hard to see so that is sometime my best guess. But its something I can control easy from the start. Thats my short and sweet hope it makes sense. Here is some pics that show ring orientation the way I like to have it.
Mike
IMG_3514 by Mike Allridge, on Flickr
IMG_3515 by Mike Allridge, on Flickr
     

[lleroy]

Of course, orienting it 90deg is better. Great advice. Thank you.

[Del the cat]

I'd flip those 90 degrees and use the rift or quarter sawn side for the string to seat on...

Yup, what he said... or whatever will look prettiest, if the wood is strong enough.
Del

[Hamish]

If its a moderate weight bow, grain orientation is unlikely to be an issue within reason(eg I wouldn't have end grain up).

Advantages... Yes 1/4 sawn would technically be the strongest.  If the wood was ever under enough force to shear, then it wouldn't shear along a single earlywood ring.

Straight grain regardless of orientation is going to have more strength than  wood milled at an angle to the grain.
A would be the best, then B. C would be the worst as the grain under the groove is angled and shortest, making it the most likely to fail.