We will shortly have a new architectural roof put up on a 1924 colonial with 1x7 tongue and groove decking. Most of the wood has held up very well for the 88 years, a few cracked pieces we can replace with extra same-size pieces from the attic floor.

Opinions from roofers vary; obviously there will have to nails coming through the decking between the roof joists. The question is where to avoid having the nails come through. Obviously hitting it through the edges where the tongue and groove is is not a great place. And if it's dead center of the decking section between the rafters there's risk of splitting the wood. One roofer told me since they know the width of each piece and the location of the joists below they can mark out some kind of template for the underlayment and shingles so they'll always know about where they are.

Does this sound right? Perhaps with the new nail guns there's less hammering overall and less stress on the wood?