No bullets from me, but...
From a usability perspective, using 1031 as the number of channels would be a bad idea. It's that sort of "inside knowledge" requirement that makes MC difficult for non-geeks to understand and use.
Using the actual channel layout, or more correctly the common format to describe a channel layout, would make more sense, so that MC knew the difference between 2.1 and 3.0, 5.1 and 6.0, etc.
If that also enabled MC to work correctly with all channel layouts when set to "Source number of channels", that would be even better.