I've recently been working on some portraits with Portra 400. With one subject in particular, who has dark skin, I found myself having difficulty with exposure - first time I've worked with this kind of skin tone.
I rate Portra 400 at box speed and in this situation I'd stopped down to f/11 on the Hasselblad, and had to give a stop extra. This was in a conservatory and the subject was basked in uniform sunlight - when the clouds finally shifted!

I don't like pushing more than a stop and having a 'black and white mind' I'm still a little cautious with colour neg expansion/contraction.
To get that stop back, is pushing to 800 advisable with such a subject? Or will this only result in added texture to her face - i.e. accentuated specular highlights/pores?