Heated bed calibration

I use this tools for RigidBot heated bed calibration.
Precondition:
Use the "Heated bed spring fitting" (http://www.thingiverse.com/thing:515186/#files) to ensure that dimension and distance are equal.
The procedure is than as follows:
1.) Turn off printer
2.) Move up Z-axis manually
3.) Place Z_axis_distance part on left and right side as visible on first picture.
4.) Move down Z-axis until gantry touches Z_axis_distance part
5.) Adjust all four heated bed screws until they are in one level with the build plate.
6.) Adjust the heated bed screws until Heated_bed_distance part fits between heated bed and steel rod (distance should be ~22[mm])
7.) Perform step 6.) for all four corners of the heated bed.
8.) Step back to step 6.) multiple times until Heated_bed_distance part fits perfectly in all corners.
9.) Secure screws with corresponding nut
9.) Turn on printer
10.) Lift up Z-axis
11.) Remove Z_axis_distance parts
12.) Adjust Z-axis switch until distan