Dupes are transporting only grams of whatever I'm sweeping because I have slime in compactors where they put the other thing, say igneous rock.
Slime is transforming to PO2, so the compactor is not full. Instead of taking the whole 1640kg they can carry and split it between multiple compactors. They take only 1000g and put it in the compactor where slime has evaporated and go back for more. So the sweeping takes cycles.
Proximity is enabled in priorities. I didn't tried without it.
Have slime in a compactor and transforming to PO2. Sweep during the operation.