Here are my self-built 3D Stereo Rig setup features:
Easy to carry along all the time and very fast to use: in a couple seconds I can go from minimum to max width. Or shoot different images with different opening anche choose the best when I work on the final Anaglyph.
I decided not to use a synch cable for portability reasons, so the final synch has to be done pressing both buttons at the same time. A small price for speed and portability.
This may mean some problems and missed shots in some situations: people and cars moving, wind, etc. But the great advantages of this method are rig size and weight and fast execution of each shot: out from the bag, turn on both cameras, choose zoom, CLICK, back in the bag.
This setup allows me to to shoot in every "difficult" situation, even when it is not too advisable to go around with a camera, even less with two.
With this setup I usually get good results keeping a minimum distance from the subject of about 1 m or less (3 ft) up to a maximum of 50-100 m (150-300 ft).
That is more or less the kind of situations in which we may want to operate. More than this is ok, but not exceedingly 3D. Fine with me. Besides, beyond those 100m, it's basically guesswork and would need a huge separation from cameras (3 m - 10 ft?), if possible, no 3D sunsets, sorry. Not feasible.
As an example, you may want to check out the pictures you will find in the gallery PLACES which I have taken from the airplane, they may possibly have a separation of 300-500m (900-1500 ft) from one shot to the other, guesswork and several attempts and useless shots.
3D Anaglyph photography, aside from a bunch of rules that have to be broken as much as possible, is lots of guesswork and trial/error process.
But thanks to the virtually no-cost of digital photography, experimentation is even more fun.