Thanks for posting these Lowboy. I agree I can’t hear a difference in the sound.
Could it be that the main benefit of using the wider tube is in the comfort of the player?
I haven’t experimented, but perhaps with a narrow tube you have to press your lips around the mouthpiece to make a good seal, whereas a wider tube may require less effort?
Its worth noting that whatever the size of the mouthpiece, as soon as the air enters the instrument it is restricted into a relatively small aperture to regulate the airflow