Managed to get a decent prime coat on the thawk today aswell as priming a necron lord and chaos lord. It was interesting to see the difference between the black and grey primer going through the air brush, the thawk had  2 coats of grey whilst the necron and chaos lords only needed the one black undercoat in my opinion.  Both primers are vallejo thinned 2 primer :1 thinner with a couple of drops of flow improver. The black went down beautifully and as I said the grey needed a bit of going over. Either way these primers are fantastic, especially as I am in no way some airbrush expert! I do think the nozzle on my airbrush, which i believe is 0.2mm might be a bit small for painting the thawk but is perfect for individual miniatures. Still not a bad job for an airbrush that came with the amazon compressor, both have done really well so far.