Ring Shank Nails
That part about the cedar siding didn't make sense to me. I would think a shorter nail would suffice if you were nailing into sheathing only.
I've tried to explain to people why you need a decking screw with no threads on the screw for the end of the screw = the thickness of the decking. So if you're screwing down 5/4" decking, you should look for a screw >/= 5/4 plus 1 inch and it should have 5/4" of smooth shank at the top.
What happens is you screw down a deck board and there is an 1/8" gap between the board the joist. As the screw pulls down, it eliminates the gap. If the screw has threads all the way to the head,however, it will not eliminate the gap.
And I think the same is true for ring-shanked nails, only it happens instantaneously as the nail is pneumatically driven. If the rings are from point to head, then there can be some gap between what you are nailing down and what you are nailing it down to.
Can you dig it?