I have read posts re: this type of question but admittedly have struggled with figuring out how to calculate all the variables to figure out what speed to set the pump on for use of solar panels.
I recently installed 5 4x12 aquasol solar panels on SW facing 8/12 pitch garage roof approximately 25feet at peak of roof, 12 feet to inlet and the return from the panels is approx. 40 feet back to equipment area from outlet at peak of roof. I have 2" piping throughout the entire pool system. I have 3 returns which are linked with piping around entire pool with uprights to each return, length approx35 to pool area then 100feet around pool,(hope that makes sense). I also have a separate line to the cozy cove, length is approx. 60feet from pump.