Compact servo auto level with optical sensor

This variant of an auto level I came up with, having looked through many other similar variants. It is quite compact in size. Dimensions 43.4 * 20 * 43.5 (h) mm. The fact is that none of the options I saw did not work properly on my printer and did not rest against the walls of the case or cling to the carriages.
In the process, I corrected the design several times and here is the latest version
The body is divided into 2 parts for convenience of printing, which will need to be glued together. For better fixation, I used 1.75 pieces of rod.
I used Emax ES09MA, an optical endstop, a spring (ideally 3.5 mm in diameter, 17 mm in length) and a rod 2.5 mm in diameter, 31 mm in length (cut off from the knitting needle)
Printed from ABS with 100% filling.
After printing up to gluing the parts of the case, you should carefully adjust the surfaces of Servo_pin and the case. He must move very freely without effort.
All holes in the model are made slightly smaller and need to be reamed. Th