As far as I've found, performance tends not to be an issue even with larger raids. I play with pretty low settings, but I also use a laptop that isn't particularly powerful to test everything; the logic being, if it works on the laptop, it should work for most players.

Even so, I'm interested in optimising everything as much as possible. So, I need detailed feedback on performance,

• During assaults. Town assaulted, faction, and number of squads is important.
  
• At new locations. How much of an impact to Erebus Black and Nova Tempest have? And new settlements that will be released in future?
  
• Any time you notice unusual performance hits that weren't there before.

If performance issues turn out to be more prevalent than I thought, then I will alter the balance of assaults to make them rarer and use more elite/fewer recruit units to reduce the overall number of NPCs running around. Erebus Black and Nova Tempest use a lot of models that aren't crucial to design - so I'll go back later on and optimise them as far as I can without breaking the aesthetic.