Suzanne, It sounds wonderful to be able to target bi-lateral breathing as you describe it. I wish I could but I cannot so breathe only to my right. I have never felt that I am hyperventilating when breathing every two, I breathe only as deeply as I need for the given speed. I think we agree that getting rid of the CO2 is the key. I absolutely agree with you that once CO2 is breathed out, the lungs will take in the air/oxygen needed. Perhaps the only difficulty might be in ultra-distance events when metabolising principally fat as glycogen stores become depleted. Burning fat needs about three times as much oxygen to produce the same amount of energy as glycogen from liver, blood and muscle depots. This will obviously have an effect on the breathing pattern in fast, long-distance swimming events even before taking into account the build-up of lactic acid, pyruvic acid and all the other clinkers of combustion.
Apart from Terry and a few of the other stars on this forum, it won't be relevant to many.