I'll use some numbered examples, though this is *not* meant to be used as a hard line here, just to make it easier to follow. The gist is 'how many of this group would be available to an army' essentially.
Unique = 1 group. The only group. Based on unit size it can be small or very big, but there's only one group of them. Rogue Squadron would be an example of a Unique (Small) group.
Rare = there are not many of this kind of group. Maybe there are five squadrons, all trained this same way. They are specialized, likely difficult to train. Some kind of black ops commando group might be a good example of this.
Uncommon = moderate number squadrons/units, all trained the same way. Scout troopers perhaps- available but not enough to fill in the rank and file
Common = lots of units. These are the rank and file. Stormtroopers, etc.
Not a hard rule, but in general it would also be more difficult to replace as you go down the ladder. Common units have many of the same unit, so replacement, either retraining or borrowing from somewhere else in the army is in theory easier than a rare group that is likely more specialized training and simply less groups.
The Size modifier is how many people are in each individual group. So a Common/Small unit would have many groups, but not many people in *each* group. A Unique/Large group would be only ONE group, but with many people in it.
Does this help?
Edited by Neri Rashal, 05 July 2019 - 05:30 AM.