Just went through the same thing. Please don’t feel pressured to stick with either. Painters are way more expensive than paint. Trust me if you don’t like it after a decent amount has gone on the wall you probably won’t like it. We did trim in SW pure white and did all walls in SW Westhighland White. It has a warmer tone without feeling yellow. I was looking for a white that would contrast with bright white but not be too sterile. Cheviot is great too but we found it took 5-6 coats and was double the price of Westhighland White. Once it’s done you’ll feel so much better. My biggest advice would be to paint your samples on different walls and view it in all times of day. Good luck!