Not sure exctly what you mean. I don't use a commercial tester, I just spin my heads on my finger. I can feel if there's any wobble to them. It doesn't help for fixing them, but it lets me know if there's wobble. 11 times out of 12 the only thing I need to do to fix a mis-aligned head is clean the insert face up with a piece of sandpaper. It doesn't always work, but the majority of the time it does.