Thanks for your thought on the 3x3 tent.
Yes, makes sense in a way, but for me I meant the coverage, and want to maximize yield, so I scrog, and the cmh doesn't truly flower a 4x4 area. And, yes, I would only use the cmh in winter, the colder months of the year, and keep many fans for adequate airflow.
I have one room to grow in, and it isnt that large a room. My 4x4 has a door on both sides, as well as the front. It's a Secret Jardin DR120. I grow in SIPs, so once the plants are in the SIPs, I generally don't move the containers. Also, once the plants are scrogged, nothing can be moved. So, having side access is imperative for this style of growing. I suppose, side access wouldn't be such a requirement if you could move your plants and containers in and out of your tent easily. SIPs have solved my poor watering practices, and I prefer to continue using them in my future grows. I suppose I should have stated that in my post to the thread. Hope that makes it clearer why side doors, or at least one on a 3x3 would be important to me.