The cross-eyed view method works much like the parallel view method
with the left and right images exchanged.
Hence, when looking at the images, the viewer must look at the left image
with the right eye and vice versa which means that the convergence angle
is fairly large. This, in turn, allows to use somewhat larger images
(more than 65mm wide).
(Note that you can look cross-eyed at parallel view images when turning
the projection plane upside-down.)
As with the parallel view method, when looking at it for the first time,
it is hard to get the images sharp because the brain thinks the focus point
is much nearer due to the large convergence angle. After some time
(contemplate!) one can overcome that.
Note that there is no way to achieve orthostereographic projection using
the cross-eyed view method since the eye rays for infinite distant objects
cross about half way in front of the projection plane. (In order to correct
for that one would have to transform it into a parallel view image.)
The 3d effect is not very well and looking longer at these images is likely
to produce eye strain.