Misaligned nocks. Are they "safe"?

[bowhunter15]

A while back I bought a dozen POC shafts,  tapered them,  and cut to length. Before knowing any better I glued the nocks on without any regard for alignment with the grain. By chance, a couple were done correctly. Some are rotated 90 degrees from ideal,  and others anywhere in between. I read somewhere that the arrows are more likely to break when the grain isn't running perpendicular to the riser. But my question is HOW LIKELY are they to break? They're spines properly for the bow and are just small game/stumping flu flus. Around 600 grains and only flying like 170-175 fps. I'd really like to shoot the rest of the arrows I bought but don't want splinters in the hand.

[PEARL DRUMS]

Breaking probably isn't the biggest concern. The spine isn't the same when the grain isn't running horizontally, as that's how they are tested and grouped.

[Hud]

The grain should be perpendicular to string and nock. The spine will be more consistent if they were matched for weight and spine. Were they straight?  Spine test the point by holding vertical on a board, if you do not have a spinner. Or roll the arrow across a flat surface with the feathers off to the side. Straighten any that wobble. Replace any points or nocks that are not on perfectly straight. Then stand close to the target and paper test them like shown on this website:
 http://elitearrows.com/proper-arrow/  

Next number each arrow, and shoot for a group at a relatively close distance if an arrow is consistently grouping to the right, for a RH shooter, it may be weak. If it is one with an incorrect alignment to the grain, replace the nock.

Repeat the process if necessary. Wood arrows will get bent and should be straighten whenever. I use the compression method, simply rub the high side of the bend (outside curve) with a screw driver, lightly, the compression will help to straighten the shaft. Good hunting.

[Bjorn]

The spine will be off. Remove the nocks and start over with those that are mis-aligned. You will always doubt them no matter what.

[Gordon Jabben]

I think they will be fine.  I have never seen more than a couple of pounds difference with the grain or across the grain.  Most are spined with a machine that doesn't know grain orientation.

We had a set that went off, when my directions were done backwards for rotating nocks to turn the bottom hen feather angled in.  They flew awful. However, when the nocks were cut off and new ones put on to match the grain and ignore the feathers, they flew fine.