Not sure about cammo on the panzer IV's I may revist them, I like the way the StuG's turned out so maybe. It's all time
For the snow I bought some cheap snow flock from Antenociti's Workshop. It looked nice when first applied with PVA but after it had dried it' didn't. To get the effect on those bases I applied about 4 layers on top of one another then dry brushed it in white.
I suspect part of the problem with this is the base colour leaching through into the flock which discolours it. It is on my mind to paint parts of some future bases white and apply flock to that to see if it works any better.