I used 10" Haida Skirl rough cedar on my house. I bought 8d and 10d ss ring siding nails from Manasquan fasteners online. I had to use the larger nails due to the thicker boards, but since they are true siding nails there was no splitting. The 10d's were for some 5/4 trim boards and special areas that needed more holding strength. As b8fish said, be sure to make a jig for the reveal and it can give you the perfect nail position to avoid splits. It was a learning experience, but by the tme I was done it was very easy and I wished I had more to do. It goes up fast!