Help CO2 baking soda + citric acid

[wiltedroses]

Hi! I think I'm going for CO2, but I can't find the proper amounts for the method from the following thread.

Thread 'Near Success! Cheap, Fast. (Baking Soda + Citric Acid)'
https://sanctioned-suicide.net/threads/near-success-cheap-fast-baking-soda-citric-acid.186524/

1. Mix baking soda and citric acid in the ziplock bag.
2. Leave the bag mostly closed, with a small opening.
3. Pour water in and quickly close the bag.
4. Wait for the bag to expand.
5. Put the ziplock bag in the trash bag with the zip side facing up.
6. Sit down and put the bag over your head so that it hangs down, with the ziplock below your face.
7. Use the rubber band to secure the trash bag around your neck.
8. Open the ziplock.

how much baking soda and citric acid would I need? I'm probably going to use a 50-litre trash bag.