Hi and welcome to WindWorks Mats.

Tongue level cannot substitute for pitch change without knowing what the aperture corners are doing.

Are there any alternate fingering positions you can use to get a lower but closer harmonic?

You will see as you work through the course why I am so keen to learn more about this instrument. I am going to source one. The relationship to the voice as mentioned in this video is very exciting.

Cheers Greg,