Nice (and minimal) work! I would like to follow your design.
I've found a 40 teeth bevel but with maximum hole of 6 mm. Did you find one with a 7 mm hole or you enlarged the hole with a drill?
How did you coupled the 7mm shaft with the 6mm hole bevel?
I've seen a cheaper motor on rs with a 20Ncm torque (vs. 30Ncm of your motor). Do you think this could fit the job?
Where did you but the voltage regulator?