Originally Posted by: Dietz 
How would _you_ set up a surround session in Reaper?
This is how I would set up a Surround 64 session in Reaper, once they invent Surround 64:

For Surround 5, I would select 6 "Track Channels" rather than 64 "Track Channels". (6 not 5, because Reaper requires an even number.)
Originally Posted by: Dietz 
If you would do so, you could use _any_ downmixing device (i.e.: multi-channel to stereo) of your choice for the dynamic mixture of up to eight individual MIR Pro output channels.
No, because MIR doesn't send Reaper 8 channels, even when I set Reaper to 8 channels. And then I see an undocumented setting named "Force output channels", and that sounds like it's designed to make MIR send whatever number of channels I need; so I ask for clarification about this undocumented thing in MIR; but no, it's not for daily for use, it's just for special, secret, undocumented situations.
Originally Posted by: Dietz 
Please understand that it's not my job to explain users the handling of their DAWs.
Okay; and you please understand that my job is to use whichever tool does the task best for my clients, and when MIR isn't that tool, that means less revenue for VSL, and that means they have less resources to pay you for your job.
Whose job is it to document "Force output channels"?