When my Refinery finishes in the heat of battle, I don’t have time to manually find 3 workers that aren’t holding any minerals.
What is the optimal way to transfer 3 workers from minerals to gas without sacrificing any minerals?
The most efficient way is to select any 3 workers, right click on the gas, then immediately hit C (return cargo). Workers that are holding minerals will drop off their minerals, and then proceed to gas. Meanwhile, workers without minerals will head straight for the gas!