Will this be an autostereogram ("Magic Eye" type picture) or one that is viewed with a stereopticon?
I have made different types of stereograms on the computer. Anaglyph. Random Dot. Stereopticon. Etc...

Interocular distance needs to be correct in relation to the size of the image and the viewing distance.
It needs to be large enough to create the stereo effect. Usually that means the average distance between a human's eyes.
It also needs to be smaller than the apparent width of the picture, given the viewing distance.

If it will be viewed on a stereopticon, it might be easier. If it will be some type of autostereogram, it might not work. The viewer might not be able to focus on it. He might have to move closer or farther away. It might give him a headache viewing it. He might not be able to see it at all.

Also, try to make both cameras converge on the same spot even if they don't see the exact same field of view. In real life, your brain uses the images from both eyes to, sort of, triangulate what it sees. You have to simulate that virtual triangle for the 3-D effect to work.