"10 parallel agents" was just one guy with access to unlimited credits. Most of us are on Max plan or API plan, and cant afford to burn credits. He can just run the agents just to show that he is running 10 parallel agents.

As an avg dev, what I can even do with 10 agents? It like managing 10 toddlers who can code, it looks good but it becomes hard to manage as you have limited context in your brain.

2 is the best setup if you can afford. One can write Tests and other can write the code. This is better because if you just use the same agent instance, its not gonna be able to write good tests as it will just write tests that its code is gonna pass. Its different for everyone else, but for me, 2 is the best setup for TDD.

Apart from that, you can just go ahead and do it your own way. I have found that many senior engineers think they are special when they can make Claude Code do something, they think its with their setup but I am usually able to replicate without any setups or Agents.md/Claude.md, the models are good enough without any complex setup.