Room within room or 3 layers of drywall for vocal booth?

Which of these would be better at isolating for a vocal booth? They're both made with 4x4 timbers for support at the corners and drywall on the sides, then acoustic caulk at the joints. The doors are drywall on hinges with weatherstripping to seal it up. The first is a room within a room with the inner booth not touching the outer booth. The second option has three layers of drywall with no greenglue used. Thoughts on the first option. The inner box is at an angle so it can be bigger but that means there's not as much space between the inner and outer booths at the corners. I'm thinking that since the timbers are at the corners that may help to block sound there so the lack of separation space isn't as much of an issue. Which would you say would be better for vocal isolation?

" doors are drywall on hinges " Eh!? Option 2- but use real doors, with frames and seals. With more info you'll get better responses.

Thanks!