A couple of things I'd like to mention here from my very limited experience with both hops.
I'm pretty certain that Two Brothers Sidekick is made with just Mosaic. If you can get that, it may provide a starting place for working it into your recipes. It will also answer some of the questions above about piney vs. citrus flavors.
In my ZD clone, I felt that there was no reason to use citra early in the boil like the recipe here on HBT does, and replaced the first addition with Mosaic, and a part of the second addition, as well as one oz of dry hop, all mosaic. I've never gotten higher praise on a beer. It's wonderful.
The advice above me in this thread seems to agree with my experience.