The knobs worked for me when I used the M3x7mm Spacers.
The longer ones for the Idler Bearings pushed the knob too far out.
I still have left over spacers. lol
You can adjust the steps by either:
in the Firmware Source Code, (personally preferred)
using the G-Code Keyword, (which I forget but google didn't)
or the LCD Menu. (MAIN -> Control -> Motion -> Step/mm -> Esteps/mm)
Changing it from the last two will not save the adjustment to exist post re-uploading the firmware.
Changing it within the firmware guarantees the change will remain after re-uploading.
EDIT: Have you done the PID Tuning for the Hot End?
Pronterface GCODE: M303 S200
M303 engages E0 hot end PID tuning for temperature target of 200 Celsius.
They tune the default for 165C but I find the plastic flows better for me between 200 and 230.
Tuning PID helps with keeping the hot end the same temp as the plastic removes heat from the heater block.
M303 reports back three numbers which you replace at line ~320 in "Configuration.h"
//#define DEFAULT_Kp 12.3 // old values stored for reference
//#define DEFAULT_Ki 0.6
//#define DEFAULT_Kd 62.32
#define DEFAULT_Kp 12.7 // new values from pronterface
#define DEFAULT_Ki 0.62
#define DEFAULT_Kd 65.55