> are more channels available other than Mono & Stereo? I see that others are greyed out on my Mac
Yes, that's my situation. Nothing is available other than Mono and Stereo.
Here's my flow of conversion for Titanium 11:
Drag files into the window
Select Convert in the row of buttons across the top
Click the red convert button in lower right
In the pop up dialogue, select QuickTime Movie as the device
For Quality, I click on Change ...
In following pop up dialogue, I select Settings ... , then for Compression Type I choose Apple ProRes 222, click OK
For Size ... , I select the original recording size
I make sure Sound is checked, but for Settings ... I'm given only Mono and Stereo. The options for other sound recordings (including 5.1 surround) are greyed out no matter what Format I select.