One thing that irks me slightly with Dark Sun is the (to myself at least) inescapable notion that the Sorcerer Kings would just bail. I struggle to believe that The Grey represents an insurmountable barrier to magic users of such power.
Perhaps the moons of Athas serve as Pleasure Planets of the Sorcerer Kings? It sounds enough like the title of a weird fiction novella to be true at least.
They would still be drawn back to Athas & the tablelands in order to maintain their city-states, if only in the interest of maintaining Rajaatās prison via the Dragonās Levy. I doubt they could delude themselves into thinking they might avert their old masterās wrath by squatting on a nearby moonā¦
When it comes to the SMs, one thing to remember is they are dragons. They are very powerful, but at the same time they are very protective of what they have. I tend to play them as obsessive and possessive, aside from extreme reasons they donāt like to leave their city states. As rebellious champions, they only really fear their master, Rajaat. In their eyes, if not in reality itself, he could chase them anywhere, any time, in the cosmos. They can not hide from him. The best they can do is keep him contained.
Combine those two things and thereās a fairly good chance theyāll stick around home and not run off to some other place.
The silt tides would likely be a LOT higher/stronger, but wind might play a big part too, because silt blows around really easily. Plus, two moons might jack the tides around weirdly (from our PoV).
TLDR, silt tides should definitely be a thing IMO, but Iād personally just keep them narrative rather than scheduled for ease of useā¦