For a given size TV and viewing distance, the 3d depth should be equal between the two formats. The 3D depth gets less the closer to the screen you get i've noticed, while the increasing the screen's size [i think] also increases the depth/popout since the same image are just getting wider on the bigger screen. You can always just think about what your eyes are doing to figure it out. The straighter your eyes are, the further away it looks and/or bigger in some cases (Great for viewing statues and other large structures). The more crossed your eyes are closer/smaller it looks.
In gaming, some people like whats called the "doll house" or "toyification" look, where you increase the width between the camera viewpoints, causing your eyes to cross to when viewing everything and making everything in the game world look like a toy set. On the other hand, there are people like myself who actually increase the maximum separation just a tad so that objects on the horizon are actually a little farther apart than my eyes are wide, giving majestic scenery a sort of majestic look, which is actually what i use in the videos in my signature. If you have something near a 46" 3DTV (and you can figure out how to download my videos onto your TV) you can see this effect yourself.