I usually try to get the best output possible, directly out of the VFB. There are two reasons for that:
1. Consistency | If I only have to deliver one image, then I could use all the render elements in post to get a desired result. If it's more however, then it becomes quite tedious to get a consisten final result for all of them. That's why I tend to go for the optimal results while still in Corona and then just do some fine tuning in post only.
2. Lazyness | The more I do in 3dm, the more flexible I am. Also, the more easy the post production is.
Generally, I try to go for a consistent and simple GI - it's either Sun + Sky (very flexible, but no clouds etc.) or a good HDRI (not so flexible, but nice reflections and a 'populated' sky). Overrides are also an option, but I do them only when I have no other option (e.g. Worked with a photographer on an
interior: He made a 360° of the surroundings, but it was not a HDRI with good illuminational value, so I used it to override the Environment, Reflections and Refractions, while still lighting up my scene with Sun and Sky).
As for the dark areas and highlights - don't forget, there's always post-production for that.
Good luck!