Particle scale height evolution of run SI30-3-2-c, run SI30-3- 4-c, and run SI30-3-8-c. Panels (from left to right): evolution of the system in simulation boxes of 0.2 × 0.2 H_g, 0.4 × 0.4 H_g, and 0.8 × 0.8 H_g, respectively. The largest particles converge to the same height in the first two cases, but particles with τ_s < 10⁻¹ are diffused to heights larger by about a factor of two. The panel on the right, where the simulation box size is the largest, shows unusual non-convergent behavior due to the development of shock-like patterns in the radial component of the gas velocity (discussed in Appendix A).