Actually it’s a planetary colonization harvesting. For this you just need to hire a local racketeer on the planet, which will look over those processes and colonists working there. Time to time he’ll travel to his family (you have to care about it), which lives at main trading hubs in 1.0 security systems, to take a golden jacuzzi, to buy some faction vessels and of course a Victorieux Luxury Yacht.
It’s the planets radius. Gas planets are generally way bigger than most other types. I look for smaller planets with decent tax rate/resources. It can be a pain finding just the right one.
And build everything close together with short routes between them.