Hi!
Finished my build of the AR4 MK3 in Finland some time ago. Even recoded the time the build took me,
52.5 hours of slow, careful and deliberate work.
Ros2 is working thanks to ycheng @ https://github.com/ycheng517/ar4_ros_driver/
Below's a sample with Chris' software (object recognition) and one with ros 2 collision aware IK.
Great job! Can you provide more detail on the optical switches used and what parts you needed to change?