We have solved numerically equations of motion for the evolution of a one-level two-dimensional F region ionospheric plasma cloud with five different ratios of cloud-to-background integrated Pedersen conductivity. The simulations show that (1) physically small clouds striate because of the gradient drift instability more rapidly than large clouds simulated previously and (2) there exists a minimum striation onset time as a function of the Pedersen conductivity ratio. Observation 1 is in agreement with the rapid striation development exhibited by the physically small Avefria barium clouds releases, relative to the large Secede or Stress type releases.