I have found with cedar arrows that, if they are on the high side of spine for a given bow, the feather contact can mess up the arrow flight a little. With those, I can often get the flight I want by turning the cock feather in, which of course puts the vane of the nock in, which messes with my head, so I put on reversed nocks. I am guilty like many others of tending to set up arrows with too high a spine, the problem is then that only the strongest shots get the proper arrow flight. I often target 135 or 145 grain heads, just to find that I need to go to 160s in the end. Even Howard Hill did not always get full power out of his bows when shooting at game. I, at times do not either, so I always check to make sure that my arrow flight is good with a bit of a shorter draw when shooting with odd positions, like the bow on its side. For me, an overly stiff arrow shows up real quick when I shoot from my knees with the bow laid on its side. I know that I lose about 3/4" draw in that position, but it is all I have in me and I have had to shoot a number of deer doing just that. My go to arrow is a 27" bop 1918, I adjust by either using glue on or screw in inserts, that 25 grains makes or breaks the set up for any given bow that I have, but one or the other has always been right. My last dozen of Acme cedars and my first dozen of Surewoods are really messing with me, I just love it when wood arrows work as good as my go to shafts. I will probably save the 1918s for another day.