The riff (those points you see where the grain runs out) should point to the front of the arrow, like this >>>>>>>>>>>> on top when the arrow is nocked.
When you cut your nocks, cut them across the grain, and wrap them as you have stated.
Leave the arrows longer than you think you'll need, and experiment with length and point weight for best flight. If they are too weak, you can build out your arrow plate to compensate.
You didn't mention what type of bow you have, but a recurve is cut closer to center than a longbow, and will require a stiffer arrow.
Good luck!