Hello, I am preparing to put some tongue and groove on the walls of one of our rooms and I have a few quetions, if anyone can help. First of all, our old house has 1x boards over the wall studs running horizontally, spaced about 8 or 10 inches apart. I am thinking about using 6" wide x 8ft T&G, running vertically. We are going to paint them. I attached a picture of the look we are shooting for. 1. In a lot of these pictures, like the one attached, you don't see knots and things like that in the boards. Are they using some sort of filler or something? It seems like if I used T&G right from the lumber yard you wouldn't get that smooth look. 2. Should I glue the T&G to the 1x's and finish nail? 3. How do I deal with warping? Let the boards sit for a while and only use the straightest ones? Any other advice would be greatly appreciated. We are really hoping that this comes out nice. Thanks a lot.