The denominations you're listing sound like bulb sizes, not necessarily brightness.
Either way, you don't want to find the brightest bulb. Have you ever ridden a car in the night with a really bright dash? You will not be able to see outside at night. Also, the bulb may be bright but if it only shines one direction the bleeding from one area on your dash/cluster to another will be obvious and this does not look good. You'll want to find a bulb with true 360 degree coverage or diffusion to not make the bleeding so obvious.