Hi, I'm going to build driveway gates, I'm pretty confident I can build out the panelling using a router to make shiplap (or a facsimile of it). Trouble is I can only seem to find ready made shiplap or feathered boards, and not thin planks. Is it reasonable for me to take 22mm thick treated wood and table saw it in half for the panelling, or plane down the feather edge, or am I missing something. (I'm incredibly new at all of this). If I did saw the 22m in half would that mean it needed treating again ?