Thanks for the detailed response.
I now see that DC tigging alum is best left to the pros not a bozo like me.
Plus even if I got high purity helium and got setup for DC tigging with helium, it woulden't make me weld any better so I'll be better served by spending the money on more blue equipment as budget allows.
I still have fun tigging so I will continue.
PS - Does your dog bite?