Random is the most important kind of modulation for granular.
-- richc90No. You need smooth, SLOW modulation waveforms to make scanning through granules easier. Do it too fast, and you don't get the right sorts of textures.
-- Lugia
Speed/smoothness has nothing to do with whether the modulation is random (think of Sloths).
Random modulation to things like position, panning, grain size, amplitude, pitch etc are all standard practice in granular synthesis (go look at any software granulator with built in modulation, or the Supercell module which has internally generated random modulation normally to the CV inputs). Whether a given kind of modulation will give you "the right textures" (whatever that means) will depend alot on the specific audio in the buffer and what results you want to achieve. That's why (for instance) the Granulator software offers you ways of randomly modulating parameters as well as more standard LFOs.
FWIW I'd get Batumi and Blinds rather than QPLFO and SISM.