I think I can justly paraphrase you as follows:

The gravity, and the qualia, are occurring inside the simulation. You only need to worry about having an actual sphere, or an actual brain, if you want to have effects outside the simulation.

Not quite. Where as with the simulation of the sphere you need to an actual sphere or equivalent mass to produce the simulated effect outside the simulation, with a simulated person you need only the simulated output of the person, not the person (or its physical components) itself, to have the same effect outside the simulation as the output of a person from outside the simulation. The improbability of having a philosophy paper copied from with the simulation that describes qualia is explained by the qualia within the simulation.