Originally Posted by aberg83
I've done it once with the allen key and found it hard to determine what was enough "light resistance" between the feeler and the rocker. I've heard that this spring-loaded tool takes away that guesswork. Or maybe the clearances don't need to be that precise?
They don't need to be that precise. As long as you can move the feeler gauge with your thumb and index finger movement only as well as feel some drag then you're good to go.