As many above, I tweak the flow rate to suit my setup and how I work.
I run 40m of microbore and 60m of gardiners reinforced pole hose on my reel. Pure freedom controller on 45. I'm happy with my setup for my speed of working (average to slow...ole git!) I know it works for me because the initial burst of water through the pump is too much and bounces back off the glass, rather than running down it, and when the battery gets low and the water flow reduces, I'm working too slowly and it's annoying. Also I know the flow is good when I can hit a neighbours dog or cat 15 feet away.
Having said all that I am intrigued!
Science dictates that there must be an optimum way to clean a window: the most efficient way around the window, plus the frames, the best flow rate, how many times over the glass, how long to rinse? And all this whilst maintaining a quality clean.
Oh well, I think my jacket spuds are done.