iPad worked great for viewing these. Zoom in as you put the iPad a few inches in front of your face and stare straight ahead. Let your brain merge the two images into a 3d composite in the center of your vision. I found taking my glasses off helped me, too.

Having remembered the trick to do these, 3 and 4 were pretty underwhelming compared to the others.

Wish the stereo images were cross-eyed mode. They're easier to see that way.