Firstly I always undercoat in black using the Games Workshop sprays. Black as a pose to white undercoat means that if you do miss a bit, say under the arms, then it just looks like shading, where as the white undercoat stands out like a sore thumb! Many people swear by white and who am I to criticise, the black does dull the colours slightly but I don't tend to go for parade ground troops anyway and I like to speed things up as much as possible. I never undercoat using a brush, the time taken would do my head in!
I tend to use plastic bottle tops with Whitetack (not Bluetack as it's not as tacky) to save handling the figures themselves.
Anyway, first picture:
Strip of figures with the first coat of Dk grey on the tunic.
That's all for now, hopefully a 10mm WSS battle report with pictures to come soon.