I don't use the meta methods.
First of all, the only cabin type worth anything imo is First Class, unless you are running Luxury tourist destination missions in a Beluga. First Class can hold better passenger types, and gets you the most credits when you are Allied with local factions.
The magical number is 54 First Class. There are no single bulk missions that require more than 54 cabins. That's 4 class 6 and a class 5, or 3 class 6 and 3 class 5. Type 7, Beluga, Conda, Cutter can run them easy.
I am allied with every faction in Cubeo, and I'll often get 48-54 capacity bulk missions to Borrelly Hub in Purungarawn (about 150k ls away from the star) or to two different stations in Lambda-1 Tucanae (both of which are over 150k ls away from the star). It takes about 8-10 minutes to make the run, and I get anywhere from 8 million to 20 million credits each time.
If I don't get a good bulk mission I get enough VIP groups going to one of the stations above to make really good credits, sometimes more than I would get for the bulk mission. For example, the VIP's can be worth 2-4 million each. If I'm in a Type 7 and I get lucky and fill all 6 cabins, that can be 12-24 million credits on average.
Again, the run takes anywhere from 8-10 minutes. Maybe 12 if you are a bit slow on occasion. Stations 150k ls away don't really take as much time to get to as many people think.
I made enough money to buy my first Cutter this way. Other methods might net you a bit more credits on average, but First Class bulk is underrated and overlooked.