Hi Beautifulmonkey. The Scylla fight can be easier for you if you stay back far enough that you only fight one head at a time. I then make sure I'm fully healed before I take on the next one.
The green fog that appears is the spawn so I avoid it til all the heads are dead and I have run around my deck removing any extra tokens there. Once I have made sure all tokens are cleaned up I still need to fight the spawn but now there is only a few it is a more manageable fight.
Now I did have to use a aquilan ship to beat this as my Mb ship didn't have a good enough wheel to keep me healed as I was fighting. I have found several good wheels since then while fighting ships in the aquilan skyways so idk maybe you'll get lucky with a drop if you are still on a Mb ship.
Hope this helps you some what.