[Carusoswi]

This question is a little like contemplating whether aperture or shutter speed should be set first (a little like that, but, of course, not exactly).

In the case of shutter speed and aperture, of course, they both directly affect exposure. I, frankly, don't know if white balance actually affects the exposure value or not. That's a question for someone with more technical knowledge to address.

On the other hand, if you are using a camera with an on-board metering system, then, if you find that changes in the white balance setting subsequent to exposure adjustments throws those adjustments off, then, re-adjust the exposure and move on.

If make your white balance adjustments first, then, by definition, you will subsequently monitor and adjust exposure. I doubt that the white balance adjustment made prior to the exposure adjustment would be affected by your subsequent exposure adjustment.

Since, obviously, the need for further exposure adjustment can readily be observed via the on-board metering system while the need for further white balance adjustment isn't displayed in real time by any camera system of which I am aware, if you really want to play it safe, then, set white balance first.

In practice, since WB is pretty much a one time adjustment, it would be set first on all but the very first shot in a given setting, anyhow. If you are controlling WB manually, you walk out into the sun and set it for daytime light temperature, then, start shooting, adjusting exposure as you go. Walk back inside where the predominant light source is tungsten, you adjust WB again, then, resume shooting.

I highly doubt there is any significant effect upon exposure exerted by a particular WB setting.

My $1.00.

Caruso