I would be very hesitant to offer that advice, because of the potential of contamination, if not from the tank then from the lubricant and who knows what all else. While the oxygen might be pure, it might not be dry, and the moisture could be serious bad karma.
the reason for industrial grade being more pure is the risk of explosion in an industrial setting is higher... there are no lubricants used in industrial grade, and they are filled the same way...
just buy yourself a tank, and if you are hesitant about exchange, have your tank refilled... hell you could probably get your medical tank refilled at the weld supply store..
and it is drier than medical grade...
industrial grade is better quality than medical grade...it has to be ( you can check this out for yourself )