I'm not at all against the use of
oximeter but would certainly get O2 bottles before buying an oximeter.

I'd get the meter before buying the bottles. You may find by using the
meter that you don't need oxygen at the altitudes you do fly, and you
may find that you need more oxygen than you thought (because you need it
lower) and that would influence whether and what size oxygen to get.

And it just bugs me that the thread title is in the possessive.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.