The trick is to stand to the side and look down at a small mirror held at an angle so you can see the focusing screen. The image will be right side up and unreversed.
This is a cool idea: I love using the WLF, except on high shots where I cannot reach it and get the shot. I've held the cam upside down but very unweildy. I'll be putting a mirror in my bag and see if I can get high shots that way without going to a prism. Thanks!
Too bad none of the makers ever thought to make a WLF that could take a mirror for this purpose. I figured it out after I got my ETR-Si but never heard anyone else talk about it. I found a small makeup mirror in the cosmetics section of a drug store. It has its own vinyl pouch and is just the right size-a little bigger than the screen.
Another usable trick is to raise the camera to eye height (using a tripod) and stand to the side. The image is upside-down, but if you are used to a view camera, that shouldn't bother you a bit!
The prism on my RB67 weighs 880g, yes nearly 2lbs. What does the GS-1 prism weigh? I really need to find a WLF for mine, some days I 'view naked' using just the focus screen when I need to take a low shot...