I can make 480k profit every ten minutes on a 6 hop round trip with 200 cargo; so that would be 96k for your 40 cargo space, every ten minutes. I could make more if I optimised the cargo space but being a combat pilot and pvper at heart, it felt wrong dropping any and all defence for the sake of a few more credits per hour when profits are already so damn high.
Note, this is not some optimised trade route, I did not pull it from a website, or spend ages finding it, I was so annoyed reading and hearing about the profits of trading compared to other trades, I decided to try it myself. I sold my asp, bought a type 7, and simply traded the most expensive items available between the station I was at, and a station I knew would have items to trade in the other direction.
The bit you are interested in, I am sure, are the items and stations, I was trading between a high population High tech and high population extraction/refinery, hauling Palladium to the high tech and either Performance enhancers or consumer tech the other. After a few hours I found rotating the consumer tech with performance enh I was not saturating the route dragging down my profit as much as I would otherwise do only trading one and not the other. The palladium price being far more per ton than anything else available, the profit V profit loss due saturation was not so much that I could make anything like the same trading an alternative on that leg of the trip.
Although I am sure you are not interested, and nor would I blame you, I became so disgusted after a few days that this sort of profit is available, so easily, that I have stopped playing until such time that the developers get a clue and the other careers are brought in line or failing that, until they reward the career paths requiring the greatest effort, and greatest player skill more than the easiest mechanic in the game.