It really comes down to personal preference. You could do two 4x4 tents, or what I plan on doing is taking my 8x4 tent and splitting it in half and having one tent for both flower and veg. The veg room, I'm using a t5 light and for flower using two gavita 6/750e flex. You'll also need fans for air movement and an inline fan and carbon filter to help smell. I keep recommending this tent and lights to people because the lights are some of the best on the market. They're a little more expensive, but completely worth the money in the long run. And those lights can be run on 120v or 240v.
Here is a link to the tent that I got.
https://www.amazon.com/gp/product/B01HNV4KHC/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1