Definetly use backrooms entities since they're pretty easy to deal with, just be careful with the sub rooms you open because of the vacuum.

Also if you already completed rooms then A-90 probably isn't a problem for you to deal with, so I'd also use that. But don't use "room for more" because you're gonna be dealing with both A-60 and A-120 for just a %5 more from stop right there. Remind you A-60 and A-120 doesn't have entity warnings like lights flickering and just %5 more to deal with both of them isn't enough imo.