-I have no direct experience with the PI zero. I always felt that it was so stripped down that by the time I bought all the input/output connection accessories, the Raspberry Pi 3 was of better value.
-I can still try to answer your questions- one about PI 1.3 and the other about Simple CV.
Lets work on Simple CV first.
---Simple CV is a python wrapper around OpenCV computer vision software:
(Check out the Raspberry PI Cookbook for a tutorial on loading SimpleCV on a Raspberry Pi.)
--Simple CV worked great for me and is a lot ‘simpler’ to use then OpenCV. Unfortunately, it seems to have lost active support (https://github.com/sightmachine/SimpleCV, since 2015) so I have been shifting to OpenCV. I still believe SimpleCV is the best way to learn computer vision, but since they no longer have help desk support, it may be best to start with OpenCV.
--In order to run Open CV, you probably need at least 100MB RAM. Complicated processing algorithms could use additional hundreds of MBs.
-Concerning PI Zero. Wikipedia provides a great survey of Raspberry PI performance,
https://en.wikipedia.org/wiki/Raspberry_Pi. A quick scan of Zero/1.3 is that 500MB RAM is available and should be good enough to get you started.
--The only tutorial I could find on loading OPenCV on a PI Zero is from Adrian Rosenbach. Believe he adds great value but be warned of the sales pitch at the end.
-It seems possible to load either SimpleCV or OpenCV on a Raspberry Pi Zero.
-It all depends on what you are trying to do,
it might run too slow, or run out of RAM (memory errors) if you have a complex problem.
-My advice is to use a Raspberry PI zero for only simple tasks such as white balance adjustments / exposure settings or time lapse measurements where there is a lot of memory managed in-between processing time available.
-Also note that the latest Raspberry PI 3 Model B+ was released Mar 14!
-Recommend posting your Raspberry PI zero application as a forum question so others with direct/more experience may be able to help.