My Hopes were fulfilled - I did finish the four Mercs just before midnight. Here are some pics of the finished cars:
I'm not sure about the black-lining, particularly on the lighter colours. I might try something different next time - doing the black lining after the primer and before the basecoats as a form of pre-shading.
That being said, I've got four very nice identically armed cars for sponsored pro autoduels or maybe amateur night at a generous arena.