Sorry, I'm still concerned about the understanding.
If you custom white balance, then use a light to insert light on the macro subject, the white balance is wrong, and will produce a red image.
With light being used, you are pretty close in color without any custom white balance for the depth.
You don't custom white balance when using light, you should set the camera kelvin to the the light's kelvin. My comment about custom white balance is in respond to your comment about subject distance to surface, it's with ambient light.