Sounds like you have done your research and are on the same page as everybody else in the industry and the world... -1. Every other day should be adequate, many people use that water for irrigation so the water is not "wasted". Filox-R, Pyrolox, etc should be backwashed according to the manufacturers recommendations, but the water temperature is often neglected to be considered. For many medias, water temperature is not as critical. For Filox/Pyrolox, it is a very important part of the calculation. Congrats on a successful install.

Regarding smaller pumps handling Filox, it is common to use 2 smaller systems so the regeneration backwash rates can be accomodated.