Ah, I'd say anything under 100km, and thats REALLY pushing it. Only the Destined are really capable of 100km, most ships would be >70
The four largest ships in my fleet would be around 90, and the second lowest 50, third lowest 30 and lowest 25. But I mean, it'd vary from ship to ship. A frigate would be smaller than a Star Destroyer-based ship, for example. I'd request people to show it when their ship(s) enter, like for example:
"As the [>100km] long ship entered the orbit of [Planet Name]...."





