Audio Unity audio setup for VR installation/exhibition!

Hey folks. I'm working a project with some serious audio requirements and it's not an area I know much about. Hoping you can help answer some questions...

While the user is seated in a custom setting, they will be surrounded by 8 speakers at head height (in addition to wearing the VR headset). During the VR experience, these speakers will play an ambient soundtrack, with foreground sound effects (binaural spatialization) played through the headset (we're thinking of using Google Resonance).

Ideally we would handle everything in Unity - which means we're looking to be able to output to approx 10 speakers in total (the 8 surrounds and the stereo headset speakers).

We were looking at Thomas Mountainborn's work, as seen on this page - https://thomasmountainborn.com/2016/06/10/sending-audio-directly-to-a-speaker-in-unity/ , but that only seems to give us a total of 8 speakers under our control, not to mention the fact we want to use the Audio Listener for the VR experience.

It's possible that we could accomplish this by syncing the 8 track audio to start at the same time as the Unity experience (possibly get Unity to speak to a web page) but we'd appreciate any ideas that anybody has on doing this all under the hood in Unity.

Much appreciated

- Rev!