i've tried setting up. The commands look like: pick up 100,000 everything from earth, next planet, unload all load all, next planet unload all, load all, next planet unload all load all > earth, unload all.
inevitably, the command chain gets borked-- theres no minerals to load, or the ships fill up, and the commands have to be entirely redone. Rather than just syaing "sorry, the 350 new mines at alpha gemeni filled us up, we'll get you on the next pass" the command simply terminates and you have to manually go in and reset how many of each mineral to load and unload again. Same thing happens if your ship arrives and tries to unload and has nothing to unload-- lets say you increased demand at a new industrial world and it empty'd the fleet-- chain borked, and the whole command sequence needs to be reset. For the logistics to work, the commands have to be noninterrupting. However, thats spooky and introduces its own problems, because we can crash our games if we set a noninterrupting commands on cycle orders (see refuel ship ad infinitum).
It sort of works if your circuit is very short, but short supply chains suck too, because theres such a short period of time between visits that the absolute mineral concentration isn't different enough to justify the visit. What I really want is for my freighter fleets to allow me to shift minerals throughout the colonies without changing the orders of the ships, but by changing the orders on the planets. So if a small forward maintenance world that stores only 1000 units of everything needs more duranium, just set the duranium higher and it fills up by my distro network, rather than by finding an idle ship and commanding it to do something once. The reserve levels are already coded, so we need is the freighter network commands.
Incidentally, it would also love fuel transfer commands to have reserve levels set, so that tankers could make similar circuits, picking up fuel from refinery worlds and distributing it, but not allowing it to pool at low-demand colonies (while keeping them topped up automagically in case you dip in).