I actually just did something similar to what you describe. A Mexicola Grande and Ettinger are about 6ft apart. They are still very small and struggling through "winter" here in northern CA [9b]. We will see and must compare notes in the future. My challenge with these Avocados is keeping them hydrated adequately - they are far more thirsty than citrus.

Look up Backyard Orchard Culture from Dave Wilson Nursery. It is applicable to all fruit trees and I practice this method in my backyard.

Here is my Gem and Carmen next to each other with them planted half in ground and half above ground with 6-8 inches of mulch over them.

@catfishhoward

here is a video I uploaded this morning on my avocado trees, its still processing the HD version.

https://www.youtube.com/watch?v=NdItGKiVDb4

Thanks for the video, I'm not so worried about them getting to big now, I'll just keep them pruned to the height I want.

Yes there is nothing wrong with growing avocado bushes :)

I saw one guy on youtube with a real productive little cado tree that looked more like groundcover as it was not more than 2 feet tall by 20 feet wide.