Let's talk about the rgb sensitivity in raw.

Good question. From what I've read, Munsell colors have to be viewed with Illuminant C in a strictly controlled viewing environment.

Anyway, my reasoning is that, as the colors have been defined, one chip will reflect measurable XYZ tristimulus values that are twice the XYZs of the other. If you double the amount of light illuminating the darker chip, twice as much will reflect, so by simple scaling the XYZs will also double and match the XYZs of the lighter chip. Since the XYZs will then be the same, both chips will stimulate the cones in the eye identically. Provided the viewing conditions, surround, background, etc. etc. are the same, the two chips will match.