| Looking at the various options you presented I suspect they would all work. I think this dive along with many others of a similar time/depth fall into the miniumum deco range or in other words there is a certain amount that you must do.
As Clare pointed out it would appear to be the intermediate stops that make a big difference (21m - 9M), and if these are not long enough then it may be too late by the time you get to 6m.
The ratio deco of 1:1 was designed to only use 1 deco gas eg 50% and not to use O2 at 6. So in theory we could do a bit less at 6m (and up).
If we beleive the Oxygen window works (whole seperate discussion), then deco on O2 at 6m is far more efficient than at 3m. This is not really reflected in any of the models. But then who says the "models" are right :-)
If I was using O2 on this dive then all I would really be prepared to do is shorten the 6m and up.
Regards
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Andy |