This is a flow test model I made to calibrate flowrate.

Print with desired layer width in vase mode (so it makes single perimeter walls) and then use calipers to check how much is the difference from what it should be and what it is (on all 4 walls).

In the picture I used a 0.8mm nozzle with 1mm layer width and after multiple calibrations with the model I got the result I wanted (the one in the picture)