I use quite a different system,I just simplify it to 2 groups.
Firstly I don't grow potatoes, because it hasn't an advantage over the ones you can buy in a shop. Partly as well because staple food takes up too much space or is eaten too fast compared to the effort (so no onions for me either)
So I grow fruit bearing instead in the first space with the most manure, like tomatoes, pumpkins, courgette, etc. Also cabbages need manure, unlike Monty said, according to me. A last group that needs fertile soil is celery/iac.
The second group that doesn't need fertile soil are pea/bean and root vegetables they come after the first group. The effect of beans fixing nitrogen in the ground is negligable because they use it themselves WHEN they produce their own fruit.