Treatment advice for tiny "studio"

Hi! Thanks for reading my post! I´m building a small studio in my basement for tracking vocals and for mixing. I´m currently working on soundproofing by building a room within a room. Drums will be samples, and guitars will be recorded in another room. After soundproofing the room will be only 2,2m wide and 3m long. Hight is 2,2m. (7,13´x 9,73´, hight 7,13´). There is a door at one end of the room (short wall). Walls and ceiling are gypsum. Floor is hardwood. I find Johns design in this example interesting: http://www.johnlsayers.com/HR/index1.htm Should I replace the slot resonators with something that will absorb more low end considering how small the room is? Would super chunk in the corners be the better choice? What should I do with the ceiling? A cloud over the listening position? Should I replace the floor with carpet? Any input is welcome!

No to carpet.