Well I can tell you what I know but it is certainly possible that the latest update has changed everything. I haven’t tried getting a freighter since the update. The fact that there is now a chance to encounter a pirate freighter definitely mixes things up… I don’t know how that might affect things though.
It used to be that you’d play until you encountered a freighter battle then load up your previous restore point so you know that next time you warp you’re going to encounter a freighter battle. You could then go to the galaxy map and select a star system, warp in, take a look at the capital freighter and decide if it’s one you like. If not, reload your restore point and choose another star system (each star system has its own capital freighter that never changes).
It’s best to choose 3 star economy systems or pirate systems when looking for a freighter. As I remember, a 3 star system has a 2% chance of spawning an S class freighter, that’s a one in 50 chance so you may have to do a lot of reloading until you get S class. Pirate systems have a better chance of S class at 5% but the freighters will have less cargo slots so you’ll need to spend more time upgrading their storage. 2 star economies only have a 1% chance of S class and 1 star economies cannot spawn an S class.
Once you find a freighter you like just keep reloading your previous save until it spawns as S class. Now, I always do it by just reloading my save and then warping in to the system, but apparently you can warp in to the system, land at the space station, exit your ship to create a new restore point and then use that restore point to keep loading from. So you’d load up that restore point, fly out the space station and the freighter battle should still be there.
To check the freighter you can ignore the battle and just fly straight in to the freighters landing bay. Exit your ship (this doesn’t create a new restore point as a save isn’t made on npc freighters) bring up your scanner and look at the floor/wall/whatever of the landing bay and it will give you the freighter info including it’s class, no need to go up to the bridge. If it’s not S class, reload your restore point and try again.
That’s how it used to work anyway. I don’t know if you can just ignore the battle anymore and fly straight in to the hangar.