[varanidguy]

Should be relatively easy. DIY CO2 Regulator should have all the parts you'd need. I'd run two separate bubble counters with two separate needle valves. A 10 lb tank should last you a long while. The parts you'd get from DIY CO2 Regulator would be much higher quality, but essentially the design you linked would be the same.

 

[varanidguy]

I just received and answer from C02Art and they stated that it is in fact 1/8 NPT fitting. Thanks to all that replied!

Awesome! Glad to see they are willing to communicate that. UNS won't even bother returning e-mails about the same thing.