no one has mentioned using
an O2 system from a home healthcare type source.
It's the same 02, the same bottles.

IN ground school I was taught that medical O2 has water in it which can
freeze in the lines at high altitudes and low pressures. I've never
used O2 so have no firsthand experience.

There may be a difference in the water specification between medical and
aviator's oxygen, but there is no practical difference. It all comes from the
same oxygen plant. There's an article on the subject at avweb.

I've never tried it, but I've been told that medical oxygen supply places want
to see your prescription, or no sale.

Dave