The main disadvantage to postwork GC is that an image exported from Poser using any of the common file formats will be 8 bit only, meaning that you have far less data to work with which limits the scope of what can be achieved. The severe banding on the ceiling of the postworked version is likely to be due to working with 8 bit data.

Poser can export 32 bit image formats but you (a) need to have software that can handle those and (b) have to have some expertise in working with such file formats.

There's an analogy to be had in photography, where you have the option to work in RAW mode (typically 12 or 14 bit) or jpg (8 bit)

I can achieve what I want in Photoshop, but using render GC is, for me, by far the easiest workflow (and, of course, it doesn't preclude postwork too).

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