So I based them black, and then did the highlighting in white from above. Zenanthal?  The airbrush is incredible for this.  Did the basing, the highlight and the initial purple for all the models in a night.  

I was then using the Leviathan contrast to do the majority of the model, as the newer genestealers have a lot of Carapace and not the slots in the back. That is when I noticed I had 3 bottles of Leviathan Purple, not blue. So they were very purple.

I am going for Table Ready.  The undersides are base colors, with little highlighting.  I have another 2 sprues of Genestealers that I will try to do better on, as well as a box of Space Hulk minis.  I don't like the poses.  Imay trade them away at some point.

I then went back over them with a heavy highlight of Night Lords blue to make them a bit more blue, so there is some contrast between the Genestealer Purple and the Leviathan Purple. It did add a bit more darkness to the models and made them a bit more blue from the purple.

Then I tested some models with Genestealer purple as the base layer for the skin areas.  It adds more contrast and the models look better. A bit more purple than the original Genestealers, but still not too bad.  

Another drybrushing of a lighter blue should bring it back closer to the original Genestealers I have, but a bit more GrimDark.