I don't really have a choice now. I must paint these models for the Greek GT (Fantasy Shop Fair) that's in next week.
Since I got all the Vallejo Air Model colours for my Imperial Guard, I will paint both of them grey. It's the easiest and fastest way for me at this point. They will both be primed black, and airbrushed with German Grey. I will do some colour modulation on the Battlewagon. Then the usual weathering routine. I didn't glue the wheels and tracks so that I will be able to place the mud and dust behind them. I think it will turn out really nice.
I don't think I will have enough time to do any elaborate painting on the Meganob. I will probably splash on the base colours and come back to him another day. Since I have a black and a white Meganob already, this one is going to be grey (and easier to paint since I can just airbrush him).
Also I am scratch building a Deff Rolla. I used the inside cardboard thingy from a toilet roll (ew!) and cut it to size. Then I glued on some thin plastic paper along it's length and some thicker one on the sides. It's just a cylinder at the moment so I still need to add spikes and the side panels that hold it on the Battlewagon. I have some length of plasticard which will be ideal for this and I am looking forward completing it.