Big shout out and thanks to Feathermind on the GameFAQs forum for helping me prepare for this and being an absolute sagacious champion and resource for the Minstrel Song community for years.
That being said, this was not clean. Dear viewer, watch this and merely use this as a template; find out how you could do better if you choose to implement this strategy on 10FS Saruin. I probably wouldn't go this route if I had to fight Saruin again. Notable moments are at about 13 and a half minutes, I had to quickly look up what the bloody hell curse even does.
There's no way to cover all the fires, even in a strategy like this. Things *will* go wrong and Saruin will find a way to mess with you, and you just have to push through.