Frank:
Contest flying isn't about using the whole day, so...If you already
have an O2 cylinder and regulator and won't be using the system much
after the contest, why not complete the system with a flow meter and
cannula?
Many of us flew / continue to fly the Western states without the MH
system. You can get 2x ~500k flights on a 13 Cu Ft cylinder with
careful use of an Oxy-miser or Oxy-saver cannula. It's about 4x ~500k
flights with my current MH system and 13 cu ft cylinder, which helps
if there is no O2 fill available. If you had the normal old 22 Cu Ft
cylinder, you'd be laughing, but I believe you have a 29.
Total expense will be less than a hundred dollars, and it's yours
forever.
Jim