I may have inadvertently created a good area for the Empire rank grind.

Isolated Empire area

That was fast.

Decided to rank up my Alt Cmdr with the Imperial Navy. Luckily my Colonized area is all Empire and all but one have a single outpost

I went from "None" 72% to "Lord" 29 % in 2 1/2 hours. I don't remember it being that fast when I did it for my main character.

Anyway, just a heads up if you can't find a decent rank run in the bubble anymore.