I have learned that with a simple heat input, a Rayleigh-Taylor instability will definitely arrise given enough time. Made it easier to see through some darkening and saturation of the ink, have to provide a user accessible controller for that. Still unsure what needs to be done to have Rayleigh-Taylor instabilities arise on a single pass through with a denser fluid falling through a less dense one, or in the aftermath of an explosion. May just need a larger simulation space, or more experimentation with physics constants. Suppose I should make all of those accessible by the user as well, in order to speed testing.