Next, I started working out the individual panels at a larger size. Working at this size on a sheet of scrap paper is very liberating. You can start over as much as you want, flop images, come back to an earlier take. There's no rule against moving from thumbs to the finished board but I do better with several stages to refine the drawings.
I ended up using that last sketch, in the lower right corner, but I cropped in tight on the guy's head and hand. If I had it to do over again I think I'd pull back a little and so that we see both characters a little better. The body language is very important here and I lost some of it when I moved in closer.