Bradetich's Double Bass:The Ultimate Challenge could answer your question with pictures (a very informative read).
He recommends a flat wrist, or slightly downward attitude for the hand (downward being the wrist is up and the knuckles slightly lowered back towards the body of the player).
No problem. There are so many great videos. I really look to Bradetich and to Rinat Ibragimov videos when I need to address a visual reference question or just need to be inspired.