Jorge O and clogz, thanks a bunch for that info. It seems that a butane/propane lighter should be suitable as long as I don't have any lawyers or government agents in my darkroom. I have one of those long nose barbeque lighters around here somewhere. If I can remove the igniter it should turn out to be the perfect solution.

I am going to run a test with half filled containers against full containers with and without gas in the half filled. I'll report back in several months.