Please correct me if I’m wrong here, but…
I did a track a few days ago, with the same kit on two slots, so that I could have polyphony. I realised that it’s possible to copy the same kit onto different slots without (I think??) taking up any more memory. If that’s true, then it’s a real bonus. You can copy the kit to a new slot, repitch, filter and trim them, and have polyphony, without using memory.
I haven’t totally explored how much this effects the memory, but I’m pretty sure it works.