I've heard numerous tales of these bulkheads breaking very easily. That lead me the same things at home depot, except they were brass. But the alcohol and acid conditions in the DIY CO2 bottle corroded it.
Then, I found the simplest, cheapest, and most effective way to have a leak proof seal. Simply drill a hole smaller than the tubes diameter and stick the tube in. Voila! 110% leak proof. You can also pull out and re-insert the tubing anytime, just like you could on a bulkhead.