It took about 2 days to make sure that absolutely everything worked, including turning stereo into 5.1 + 2, and adding LFE to the adjoining room speakers so they didn't miss out on multichannel bass. Technically, I could map the extra channels from a 7.1 or 9.1 source into their nearest 5.1 neighbors, but I left that part disabled because I don't have any sources with that many channels.
The most tedious part of the setup was proving that each source type was supported, and all the speaker mappings were correct. Test files are extremely useful and there's no one source for all of them. I spent quite some time finding these files for myself.