Another thing you can do is passenger missions from Robigo that give around 100 mil per hour using a Python. you'll have enough money for a Python after a couple of hours using your Dolphin. I still think it's better to sell your Dolphin and get a T6, but the Dolphin will work. Watch the video in detail and don't skip. Pay attention to the bit about Road to Riches and about storing a cabin to fit a fuel scoop.I am using a dophin anyway, I can turn that into a mining ship? It ain't munch good for high level passenger missions. So its just a joke too me.
Final loadout for Dolphin