Do some research about room dimensions. If you can only go for 10 feet, then it's okay. But if you are flexible, then go with 20 ft x 12 ft or 21ft x 14 ft for a better experience. The
audioadvice website had a home theatre design tool that was perfect for initial stage planning. It was fun, but I don't know if they are doing that service for free now. You can check it.
To me, local carpenters or workers have limited knowledge about soundproofing works, so if you are doing it that way, I don't recommend it. (It's a personal option of me), so you can give the soundproofing work to a theatre consultant or a professional soundproofing team for a neat and efficent work.
You check this website for soundproofing materials and products. They also calculate the material quantity according to your room dimensions. with a fee.
https://www.auralexchange.com/