and i was wondering if i could build something like this...

now the problems i have are as follwed:
1:will a 1/2" hose have enough flow?
2:will a 1" or 1/2" blow gun have enough flow?
now i cant use a sprinkler valve as they stay opened and you need a air comp to use it for semi-auto and i want this portable so is there a valve i could use to make it semi auto as a blow gun you can open and close it.
i just had an idea, what happens if i used a sprinkler valve and used the second tank to keep a constant air supply to open and close the valve? would this work? would this gun be powerful enough at 150psi shooting paintballs and each fire extinguisher holds 3liters i think...
any suggestions,ideas or constructive critasism(sp?)?