In a DIY CO2 system, a metering valve is useless. You won't produce enough CO2 to possibly cause any harm to any fauna, but that's not important.
The DIY here is not for bottle and yeast setup.
please read the last line
Please let me know if you see any other metering valves that not here and can be used in our DIY CO2 pressurized system.
It is the DIY precision CO2 flow pressurize system that hooks on a CO2 tank.