I tried a DC ub once on and order with yellow and blue wb on top. It did not work as expected. Once the ub is printed, there was much more saturation of the fabric left to get the top color opaque enough, so it came out light and pastel. If I triple printed the colors they would be passable, but still not right.
It might work with a super high pigment load top wb color, but I'm not sure I'll try it again.