Witha python run some Rares. Pick up rares at Lave, Diso, Zaonce, Orrere, Leetsi, and Uszaa...they are all about 6 LYs from each other then run them to some distant port. Need to go at least 100 LYs. Run to Palola in Kekenk of Herzong City in Shonessa something like 170 LYs and you'll get max value. You'll make 16,000-20,000 per Ton. Remember you can only pick so many rares at a time. Still make the Lave loop twice over about 30 mins and you should be able to make 1 million per trip if you go far enough. Not great compared to BH but better than nothing.
Yeah, rares are fine if you're relegated to a tiny cargo hold (from what I can tell).
If you're doing big cargo hauls, I still think A-B-A trading with Slaves or Gold / Palladium etc is a better bet.