Blender Problem with wrist bending (Game model)

noxtech

Hello, i am looking for all week and can't find any tut/information on how to do realistic wrist bending for Blender.
If any one know what mistakes i'v done plz tell me, Really want to make it realistic.

I used "Rigify" so maybe i placed bone's in wrong places and that causing this horrible bend.

noxtech

Not generated bone's

noxtech

And other question how to do weight painting mirror to other side bone's, Because vertex group make's a 45% copy rest is a fail, mirror modifier works but has a glitch and look's untrusted. I use 2.75v of Blender