When a Dragon random encounter is rolled, how does one determine how many, and how old, the dragons are?
Not an Autarch, but:
At least in my campaign, based on the relative HD and abilities of dragons, I would roll:
Wilderness: 2d6, take the lower die.
Dungeon: Use the dungeon level as the roll result.
2: Very Young
6: Mature Adult
In both cases, if you want a HD 14+ dragon, you would place it manually, much like you would a 14th level Emperor.