From my experience with Gaze-Farming, there are three different drop chances for Dragons inside the Gaze. There are always two Dragons with a quite high drop chance, followed by two with a slightly lower chance and the rare of course.
Methus Palace for example has Charred Crystal, Dark Shadow, Elegant Ink, Nerroth and Elaris in it. While I've already gotten around 40-45 eggs of Charred Crystal and Dark Shadow, the egg stacks from Nerroth and Ink are currently at 20-25 (and no Elaris ofc...). Difference can be seen there, the scenario is the same for every other dungeon.