Originally posted by Orion:
If the arrow is well matched to the bow, really doesn't make much difference. I shoot in and out. Cock feather in seems to give just a tad better clearance. Some folks really like cock feather up. If that works, then cock feather down should work just as well. Hmmmmm.
X2
If a bow and arrow is properly tuned, it won't make any difference. The fletching will never contact the riser (unless its shelf is very wide); the fletch will bend around it.
Unfortunately, it's been my observation that most "trad" guys shoot arrows that are way too stiff, so they have raise their nocking points and manipulate their fletching to avoid contact.
If we're getting clearance issues, cock feather "in" will have the least contact.
You may find this video interesting: