I installed my ObXidians about 2 weeks ago. Due to a large, month-long project, I did not have the time to twiddle around and just increased Filament Flow by 50% for PLA Marble (18 from 12) and 25% for PLA with a flow rates above 20. Works beautifully
But to get proper values, you can always do Max Flow Rate testing. Most posts I have seen in the forum seem to have max flow rate increases up to 60%
I did not change any of the speed settings. I only changed the Max flow rate in the filament settings (Edit filament => 1st filament tab, all the way at the bottom).