I just got a VFG in anticipation of mounting on my SEBR.

Now when you were being brought up and taught shooting there probably weren't any such things as vertical foregrips.

So what is the perceived wisdom on hand placement on VFG's?

Should you hold the grip at 90 degrees with your offhand or bend your wrist and try and hold it parallel to the line of the rifle?

I have seen VFG's on service rifles being used in Afghanistan and Iraq - does the military offer some guidance on how these should be held?

My opinion is that you should hold it so that it is comfortable to YOU.  

Quoted: My opinion is that you should hold it so that it is comfortable to YOU.

I agree with this statement. You are going to have some that say hold it one way and some that say hold it another. You have to be comfortable with the way YOU hold it. What is right for one is wrong for another.

Agreed. What works best for you. I do the "fonzie" hold.... thumb up.