Congrats on using cattle panels. I previously used concrete screen. More expensive, thinner gauge, no coating.

But, do buy 16' pieces and cut them in half. Heavier steel and way cheaper. 8ft 2=$44 vs 16' $29. 4ga vs 6ga.

I plant 6 tomatoes, 18" apart. (close!). 5 gaps = 90".
Two panels, 18" apart for the front and back. Then, cut more panels, fencing, whatever to join front and backs, every 18". You end up with a long rectangle of 18" squares. The tomatoes centered.

Also, I'm adding another plot, built as above, but with a second row along one face. One rectangle, with a second row. A combo of my design as well as the one above. Also, we live in a super windy area. So, I want the support on 4 sides of the plant. Not just down the center.