I always just stand arrows up and spin real fast like a old top toy and watch for any wobble at the head. The kind you lay down I think they put arrow in it and spin nice and slow and watch the tip to see if it is spinning true or you can see it move up and down and left and right as you turn it. The wobble comes from the head and the arrow not being perfectly flat with each other and as you tighten down your head it will pull it one way or the other. A cheap quick fix can be to put a O ring on as you are putting on your head and then the O ring will help give you some forgiveness and can correct this. Another way is to use a ASD by G5. ASD is ARROW SQUARING DEVICE. And you can square up the end of your shaft and this helps with this also.