The most realistic answer is the best:

Go sit in front of a mirror in the pose you want to pose V4 in, and look.

WHERE does your body Bend....Twist...

I never buy poses, I use my mirror.

Ps, from your example?? The right thight has to come upwards in order for the hip to go down.

If you sit like that???
What parts are pushing into the cussion?? And how are they bended/twisted??
Go, sit like that, and look.

And before you start posing, remove ALL IK you can find and throw them as far as they want to fly :-).
Euh, NO => NO LOL. The are a PITA. (at best)

For Poses and light... 2 things you can buy but rarely work out of the box.
I use my eyes and look at real poses and real light.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!