I've planed down the cedar and our installer did a temporary install on these boards so we could get the spacing right. There will be additional pieces of wood installed at the top and bottom that will hide the ends of the slats.my past mistakes; we'll be finishing before the final install.
I was planning to paint them, but we seem to be out of that white color paint. But we do have lots of the opaque white stain we used on the pergola and fence, so I'm considering staining instead. I really don't understand the difference in durability.