Thanks, yeah, that's exactly it. I mean I can see that there's a bit of green in his skintone but so there is in that Senator screening picture and the walls are quite green there and you need to find a ballance where everything looks at least pretty much the way it should.
And I'm really happy with how this particular scene turned out, except for the skintones being too orange in the shots before Tarkin and Vader come in, which I've already fixed now.