The cargo loader and unloader move 1 time at a time, and I put stacks of supplies so loading or unloading can take a pretty long time. It's 14 slots/stacks at rate of about 1.5-2(rough guess) items per second so about 7 to 9 minutes. I was thinking of either a speed upgrade or stack size upgrade. (ie transfer faster, or move stacks of items per tick.) I'm not sure which would be easier adding an upgrade slot to them or adding a higher tier machine. I also think that if you do the stack upgrade it should be expensive about equivalent to tier 3 machine, and the speed upgrade equivalent to a tier 2 machine. I'm also not sure how it will affect them since (iirc) they are chunk loaders as well.