White balance is different to individual visibility as you've noticed. You can achieve white balance over a wide range of mixtures and in doing so produce many differing shades of white Which is most pleasing to the eye is a matter for individuality and personal preference and tuning. (In chroma don't focus your attention so much on the spot and "X" as the larger feint white triangle and you'll see the white balance area is actually quite large).
The main point behind a programme like Chroma or even guidline ratios produced from experience, is to give a guideline as to how much power of each module you should buy for any given overall power figure to allow you to achieve a reasonable white without wasting large amounts of power due to adjustment, as to do it that way effectively wastes money on modules that could have been smaller and thus money that could have been used elsehere.
Also, as pointed out in the heated discussion above, the brightness of individual colours depends not only on the wavelength or power, but also the ambient brightness of the situation in which it is viewed as the eye has a differeing colour response according to whether its totally dark, dim or daylight.