Staying hands off

Both my sophomore and freshman classes are working on an essay. In both cases a fellow teacher and I wrote the prompts together. Typically, my coworker has a tendency to be much more structured than I am and gives her students specific instructions on how many paragraphs to include, topic sentences, context, 2 pieces of evidence per paragraph, analysis, concluding sentences etc. In all fairness, her guidelines align with those expressed by my department and often produce decent products. I on the other hand, prefer to give students a prompt and allow them to make decisions about how many pieces of evidence they think they need, how many paragraphs are appropriate, etc. My coworker decided to try it "my way" and is anxious about the lack of instruction (though also excited to try something new). Her anxiety unintentionally brought out mine. Should I be giving students more structure? I have read and learned that writing does not follow the rigid rules often taught in English classrooms, but how hands off should I be? 

          I always have students submit their thesis statements for approval so as to make sure that they are answering all parts of the prompt, and I often encourage students to see me during office hours or class time but I have started wondering if I am being too hands off. I think this may be a momentary stress, as usually I feel pretty confident in what I am doing, but for now I am struggling with how much guidance is too much vs. too little.