Well although they are not fully painted the theme was inquisitorial storm troopers in BlackHawk Helicopters. The valkyries are black. I did finish the inside paint job to add a red light effect and a green light effect in the other. I used washes to get a weak lighting effect. I think I can run them as transports for the inquisitors or the warbands because the Greyknight codex refers to them as retinues(page 48). The imperial armor book erratta refers to inquisitors and their retinues. By reading that in the most open way it can mean that an inquisitor alone or with a war band, and a warband itself could take a valkyrie as a transport. I would settle in the middle to say that a warband attached with an Inquisitor is a retinue and with the Inquisitor take a Valkyrie as a transport.
This may fall into a Ruled as Intended. I am reading up on the tactics of grey knights and it seems that I can do a Coteaz army.