From my previous attempt at an Occlusion pass, which I really like some aspects of that make it look like pieces of cardboard in my world, I've tried playing with some settings to brighten it up.
I haven't got there yet but here's some more tests.
Figure 01. Previous Attempt
I like figure 03, although I feel it doesn't have enough shadow to really feel the cells are resting on the conveyor belt. I still like figure 01 the most although it needs a lot more light in there....