My setup happens to work right now, but I'd prefer more space if I could get it. I wasn't planning on 8 chickens, only 5, and started out with 5, but... things happened, and I ended up adding 3 more. I've maxed out the coop capacity and more than maxed out the top roost capacity. How big is your coop? I'd say if you are able to give them more than 7 feet, then give them more than 7 feet. You never know... you might end up adding more birds, or they may end up fighting for the best sleeping spots, or you may have a bully, etc. etc. It's good to plan for potential trouble scenarios and give yourself extra room if you can. Just make sure that all birds are able to roost at the same height. Vertical arrangement is strictly pecking order driven, and some might get bullied to the bottom or not allowed up, which can worsen the power dynamics. Vertical equality helps keep the peace

It's good to have a "just in case" lower roost somewhere, for birds that are too young, too old, or injured, and unable to get to the top roost or stay there. Though a ramp may help with that.