I'm getting ready to install about 3-1/2 bundles (76 sqft?) of cedar shingles on the gables of small cabin. Is there an easy way to calculate the number of nails I'll need for this? They'll be going into 7/16" OSB so planning on 1-1/4 to 1-1/2" long nails....should the be 5,6, or 7d nails? I have a bunch of 8d is that bad?