"Set zero to 1000m and engage the VR Soldier at 1000m. Watch as the rounds pass over his head. Now set zero to 900m and engage. Now you should be hitting him."

This is also the case with a suppressed MAR-10.

I did not know both are considered correct. In my experience however, "bandana" is more commonly used.
The wikitionary entry for "bandanna" just states it's an alternative spelling. "Bandana" has a much larger entry.

The attached image is just some Photoshop magic, to give you an idea what it could look like.

There's a point when variety is just there for the sake of variety, and this is that point.
In real life, you wouldn't pick a certain fore grip over another because it "decreases vertical recoil" more. It just doesn't, that's not how they work. It's all in how you handle your weapon. You'd use what you're most comfortable with and what makes you shoot best. This is different for everyone, but the end result is generally the same across the board: a good shooter, as good as you can be.
The best and simplest way to portray this in Arma is to not portray it. It'll just be an unnecessary complication to an already complex game with nothing to show for it.

Similarly, if you deploy it on an up-slope you'll float in mid-air aiming into the hillside.