My T1-11 siding overlaps at the top, instead of using z flashing. There is no sheathing under the t1-11. It serves as both sheathing and siding. I need to replace the bottom portion and do not want to remove the top piece of siding. I can remove the bottom portion of siding by cutting through the nails with a reciprocating saw. I'm looking for some options on how to fasten the siding to the top plate. One option would be for me to use 3 1/2in ring shank galvanized nails and go through the both pieces of siding and into the top plate. Another option is for me to drill a pilot hole through the top siding that is the diameter of the nail head. I would then use an 8d nail and use a nail setter to set the nail flush with the bottom siding.