So I was thinking the other day, and realised that there was a better way for me to make the base coats on my figures.
I use a grey undercoating medium (grey liquitex gesso - I have nowhere that I can spray prime) and needing a blue-grey colour, I wondered if using the blue GW wash would give me the right colouring. I bought a bottle and tried it out last night and it works brilliantly. Using 2 coats to get a nice even coverage and get rid of any obvious pooling look. In relatively short order last night I was able to get the blue coat onto one terminator and do a first coat on all 6 of my new Long Fangs. Its a great technique as it also manages to do shading for you at the same time.
Its not exactly the same as painting with fenris grey and washing as my previous technique was, but I'm going to continue with that technique for the units I have already begun to paint, but use this technique for my newer units - its close enough to not be obviously noticeable, but at the same time will be nice to use to differentiate the rank and file that I have already painted from the newer, more specialised units that I am beginning to paint.