SSnPP project - lighting setup

So... some of you may already know I'm retooling Sally Sprocket & Piston Pete as a student project (for the second time this year). The idea is to pitch the story as a possible animated feature.

Here's the first of 6 key scenes I have to turn into a fully colored, detailed painting. But before I can get to coloring/detailing, I need to figure out my lighting setup. The lighting sets the mood above all else.

I'm... a little ambivalent about which of these variants to go with, and you guys are familiar with this scene, so I'm interested to hear your feedback.

_{::will probably Scrap this away at the end of the week:: by then I should already be well underway with the coloring/detailing, given time constraints.}