I've been wondering lately if there might be an innate correspondence between the three qualities and the atomic motions, being falling, recoiling (10.44), and swerving. Epíkouros writes to Hēródotos that the βάρους (bárous) "burden" (so I'm translating to avoid any modern ideas) justifies why any one particle falls (10.61). I don't find it being directly expressed, but I imagine that the μεγέθους (megéthous) "magnitude" partially determines the manner in which any two particular rebound off of each other, as the case when particles of different, atomic sizes collide.
I've never been conceptually satisfied with my own model of "the swerving", but I toy with the idea that the particular σχήματος (skhēmatos) "scheme" of a particle results in a swerve ... I personally imagine the schemes as being like the different shapes in Tetris and the rotating blocks skipping spaces when you turn them as being a crude example of a kind of lateral swerve.
That may be totally off, but it's also a concept for which we have the least, thorough documentation. just to note those instances, so far as I know, we've got Philódēmos' On Signs (36.12-13), Cicero's On Ends of Good and Evil (where a character dismisses the swerve as an "arbitrary fiction"), Diogénēs of Oìnóanda's inscription in refuting Dēmókritos (fr. 54, col. 3, no. 6), and Lucretius (Book II). So, anyway ... I've been thinking "Tetris" lately with regards to the unpredictable wiggle.