Here is the sixth battery in the trunk. I used a 1" wide steel bar underneath the car to anchor the threaded rods. This battery just sits on the trunk bottom.
Just to be safe I cut out notches in the angle iron to avoid touching the terminal posts.
Since there is a open space further out on the hood, to the left in the above picture I cut a small piece of 1" flat steel and moved the threaded rod further to the left. That worked quite well and cleared the hood. Everything seems to fit quite well.