Sentra I gave this some thought and I am a solution oriented type of person so here goes.
You use a lot of EOC, which may also kill the preheat to your O2 sensor. If the sensor cools off enough due to the lack of power to preheat the sensor then you may be able to mitigate the issue considerably by making the preheat work during the engine off coasting portion of your glides. Keep the stove on when the engine is off so to say.
Another method of increasing the heat retention of the catalyst would be to have it ceramic coated, or to cover it with fire proof insulation and maybe an additional metal cover over the insulation. In the old days asbestos would have been ideal, but that's a nasty thing to mess these days.
The heated sensor would provide you with open loop operation virtually immediately on restart, so you would definitely improve the emissions going to the cat. It may be that your system does this already, but if not then a slight mod.
The heat retention using additional insulation would most likely vastly improve the average temp of the cat and it's ability to do it's job properly.
It seems like you have the instrumentation to verify any improvement, and I hope it meets your goals without costing you too much economy. Heck who knows it may actually help your economy but that may be wishful thinking, but if so then you would know you have maintained your sense of personal integrity and environmental responsibility.
Don't be too hard on him Metro, his concerns may actually lead us to a solution, which is a benefit to all who use the highest levels of technique. I think it might be possible to have the best of both worlds, and the maintaining of heat to the sensor is really the key to precision mixture control.
Anyway, that's my story and I am sticking to it for now. Let us know how it goes, and if I can help you can count on me, especially since us home boys on the right coast get pollution from all over the country.
Just trying to inject a little humor.
Mech