Now you're getting into some of the more technical aspects of multi-dish setups and I don't recall all the details from '85 when I took that course. The coolest thing I remember is that there was an international collaboration of scientists that would share data from their respective radio telescopes such that the effective dish size was the Earth's diameter. Data taken from countries latitudinally (is that a word?) from one end of the Earth to the other would be compiled and crunched to give a picture of a given section of sky with tremendous resolution. This would seem to support your observation of the elliptical dish - wide is better as opposed to tall and skinny. But maybe this is true because all geostationary satellites are along the equator.
If you look up VLA (very large array), San Agustin, New Mexico, you'll see the best example of an array of dishes working as one. I think this was even shown in the movie "Contact" with Jodie Foster, near the end of it.
By the way, have you seen photos of the Arecibo dish? Awesome eh!!!
