ok i need some feedback. for a 40 square house i might shoot 1 or 2 nails just a tad low, if the next shingle covers some of it i just use a nail punch to sink it like 1/16th then ill geocell it. **** just typing i realized i would probably save more time tearing it off. ha! anyway i got bitched out today because of that. i was inspecting the finshed job and found a nail barly exposed, so i doctored it up. is that hack work really dont see how it would ever leak or anyone would see it from the ground. there for i never seen it as a problem.