Subject: What is the optimum mix of hydrogen gas and helium gas for maximum lift

I am preparing to build an airship. I would like to know the 
optimum mix of hydrogen and helium gases for max lift and minimum 
flammability. Are there significant weight savings (overall gas 
mass)? Is the amount of lift gained substantial enough to justify 
the mix ? Any horror or success stories from the past on this 
subject ? Thanks and may your herds and camels increase 
exponentially !!
Rocky

Re: What is the optimum mix of hydrogen gas and helium gas for maximum lift