Ok, so we fixed the turn off / turn on problem. Required some major editing of the Cocuy source (brought in a specialist who found a lot of bugs in there). So that's fixed, though not sure I could post the fix here as it would require posting modifications to lots of the main source file. Also discovered that Cocuy does NOT properly sort with particle effects (it clips them away). To fix that, just add ZWrite Off to the Cocuy/Material Renderer shader.