they mix,
They are also pretty awesome. I have been using them to build up a test scheme on my eldar. I would go get a picture but thats in the garage and its freezing!
I would recommend them to anyone with an airbrush
tbh, they look light in that photo, but a couple layers and it gets pretty dark. They are transparent and they are awesome with a little preshading. The blue will get reasonably dark with layers, think darker than ultramarines (slightly), or will stay icy with a light coat. also as they are transparent they can be awesome for blending in some darker blues over some already blue models.
Whats your scheme?
ah just and went and looked,
yeh I think you'll like ghost tints

They have a slightly glossy look anyway, but if you base them in a light metalic, then blue over that. or simply blue over white for an non metallic look.
like these?
I think tints would work well on these. a little light layer of green in some shadow areas, then blue over that to get a nice blue with some blends. Then for the rust they've done below I actually think either pigments or oil washes would be your best bet, as pigments give a really nice grainy effect, or oil washes give you the total control.