Perhaps you missed my second post:

There is no minimum flow rate and given the size of the filter, you will never reach the maximum flow rate so the filter is not even an issue here.

If you want the most energy efficient (gallons/watt-hr) setting for the EcoStar, that would be around 1000 RPM. You would just need to set the run time long enough to clean your pool.
Start with 6 hours and see how that works.