I LOVE reading your posts. I learn the most interesting stuff! I particularly appreciate your taking time to educate me in such detail about this new tankless technology.
This would be a retrofit situation, but we have completely re-plumbed the entire house all clear from the street mains (gas lines and all). All of the hot/cold water lines to each zone in our home (kitchen, laundry, each individual bath, etc.) are now fed with individual 3/4" copper lines, and then they branch off within that zone with 1/2" to each fixture (no more than 3 on a line). I should certainly hope that would be sufficient to operate this system, because it was a heck of a lot of work!