1. Which is better acoustically for mixing, wood flooring or carpet?
2. Is there another suggestion that may be better for flooring?
3. Does size really matter? My room is 10.5 ft W by 7.0 ft H by 38.0 ft L. I am in my basement and I have no other choice at this time. I work on learning my room daily and I want to get it as close to acoustically truthful as possible. I'm a DIY engineer, I have treated my walls and ceiling, and I am wanting to do my floors now. I am open to all suggestions.

Thanks!

Have a hard, concrete floor. You can stick wood or laminate on to this (after a waterproofing layer). Then try with or without (loose) carpet on top, and hear which you prefer.

Good luck!