Thank you amrad. I have the BM fan deck at home with weekend so that helps with visualizing the colors together. I should have mentioned that I will be repainting the now pale yellow walls to BM Hawthorne Yellow (well, at least I think that now, we'll see after the test pot goes up). Would that change your recommendation?

Test both in huge samples on your walls. All color varies with exposure and its setting. Nobody here has YOUR room or your house. Paint the whole wall. There is no better way. In fact, to truly know is to paint all four walls. Simply white is warmer, but can take on a yellow green cast depending time of day, and exposure. If you are trying to paint a dim room into the light? I never find that successful. Try a "color" versus white and yes white is a color. white is at it's best in lots of natural light, multiple exposures. . A primarily northern exposure generally is not that. A "swatch" is several feet by several feet, and on several walls. : ) Best way is LARGE poster boards and move them around.......or just roll. All paint needs two coats, anyway. Your trim choice also matters.

I had Navajo white in my old house, it definitely leans yellow. I’d be more inclined to stick with all white to play nice with all your elements.

I think Simply White can go both ways, so that is a good pick, depending upon what furnishings you have and what your light is coming into your room. Chantilly Lace and Decorator White and Ice Mist are cooler I think. And then there is always the white primer! If you have a traditional Spanish home, does that mean you have a lot of wood, maybe cast iron, maybe saltillo tile? Simply White would go very nicely with the warmth of dark wood floors and doors, and deeply colored upholstered or leather furniture. In an all white kitchen, think if you want everything the exact same paint. You do want a little depth. If not a different color for the trim, try a different sheen. (For the fingerprints, if nothing else, I am a messy cook!)