The "spin the entire stack" was an interesting approach to staging as well. It is theoretically very simple and elegant, by just using the existing RCS thrusters for separating. It wasn't clear to me if this also obviates the need for a propellant settling burn on StarShip. I'd think it wouldn't, but I'm not sure. There is still a thin atmosphere at the staging altitude, so if StarShip is pointed in the right direction after separating, it should be de-accelerating slightly in the direction of travel.