Both the SS and DS images were processed identically in each pair, same sharpening, same stretch. What was apparent is there is more dynamic range in the DS data, it takes up a wider portion of the histogram. I used the same exposure (8ms) for both, just increased the gain in the DS image to get same brightness on the histogram.
I like the single stack, but the double stack is my preference! The Quark setup looks like this:
