Cecil,
You plan sounds like a winner, I have seen fish shipped in a very similar way, with a lot less monitoring, as the containers were in airplanes for 12 hours or more.
The cooler will also help maintain the temps. All of the shipping I have seen uses either foam boxes with the oxygen inflated bags or foam insulated boxes filled with water and the oxygen being feed into them.
On this end they pipe the oxygen into the foam insulated boxes which allows them to fill the box/cooler to the brim with water. They ship that set up by train for about 9 hours, then break it down into oxygen filled plastic bags which are placed in foam boxes for the plane ride.
Might try 3 bags that fit in the cooler or several coolers and more bags, all your eggs in one basket sort of thing.
