Yuuuuuup!
Reaper is totally working as the target audio app.
I just recorded my video (with audio from both Sonar/system sound AND the mic on one stereo track via Voicemeeter) AND in Reaper on one track the output from Sonar and in a second the output of my mic... both totally isolated from each other.
There weren't any significant audio or video glitches (one quick little hiccup but I haven't done any tweaks to this setup at all yet).
Soooooooo... this is pretty awesome. I now have THREE audio tracks as a result of this.
The one on the Mirillis Action! video that is of course sync'd right up to the video on screen.
One for my voiceover mic (recorded in track 1 of Reaper from the second stereo channel virtual output of Voicemeeter... so Channels 3/4... but I could have chosen a mono signal as well in Reaper if I wanted and it would have worked).
One for the Sonar output/system sounds (recorded in track 2 of Reaper using the fourth stereo channel virtual output from voicemeeter... so channels 7/8).
This is actually almost better than what I was chasing because NOW I can use the fully mixed audio from the Mirillis Action! recording as a "bed/guide" track in whatever video editing software I use (or inside Sonar) to line up the two isolated tracks created by Reaper.
Freaking excellent. Three days of completely destroying my brain chasing this setup.
Nest step. Completely destroying my brain figuring out which video editing software to use (and how to use it) to put the final step of my evil plan into action.
And I guess I gotta learn some Reaper basics as well but I intended to do an in depth study of it at some point anyway as an alternate DAW.
On a side note... Reaper is snappy as sh*t on my DAW. Totally expected that but really... wicked snappy even with Sonar running.
Ugly and awkward as sin though but hey... I've got Sonar for my fancy artsy fartwad needs.
I hope ya'll have found my recent adventure entertaining and perhaps educational.
Cheeeeeeers!!!!