I like the instances idea, and I thought it might be fun to add a tactical layer to it. I am a big fan of cinematic duels, so, taking a page from Apocalypse World, the Apocalypse World: Dark Ages playtest, and a post about single combat from John Harper, I put together the following idea:
https://docs.google.com/document/d/1TvwDQRJG7Iq_NSNqufO73e4E_cOiGuUQIjL4QFbxsro/edit?usp=sharing