So, even if you may not find it suitable to use the extinguishers in your build, it is worth while taking them - if they are filled, as you will get through CO2 quickly during testing, and having access to them FOC helps out during the build and testing stages. Plus some smaller events do not supply CO2 - so you can bring along your own supply to fill up your paintball tanks.

For buffer tanks in smaller builds, get hold of 7oz or 4oz paintball tanks - difficult, or get hold of fire extinguisher co2 cartridges (these are the things inside water, powder extinguishers that make them work) these asre good for small buffer tanks - google "fire extinguisher cartridge co2" for several stockists including zoro.