I am using a Harvesting setup like this:
Harvesting Station Fleet
- 1x
Refueling Hub Station (with a refueling hub module, few sorium harvesters, and a lot of Fuel tanks like 25-50mil) It is marked as a tanker, its refueling priority is set to 1, and Fuel reserved to 0 (~150k ton).
- quantity depends on gas giant accessibility,
Sorium Harvesting station (with a lot of sorium harvesters and some Fuel tanks like 1mil, and also refueling system) It is marked as a tanker, its refueling priority is set to 10, in a fleet window it is set up to "refuel own fleet tankers" (~125k ton or larger).
Sorium harvesters will automatically pump fuel to the Refueling Hub.
That way I can easily adjust the fuel produced by just towing Sorium Harvester Station to a desired Fuel Harvester. And I don't need to build huge fuel harvesting stations like 1000k tons and tow it for years to a gas giant in another system.