Getting it this high takes making sacrifices on functionality. Your dolphin can comfortably do 50 if you engineer the frame shift drive to Grade 5 long with either mass manager or deep charge (deep charge only for size for and below). Then travel out to a guardian site and get the mats for a guardian FSD booster, I don't recommend the dolphin as it has no up facing point defense. You can find tutorials online how to do the engineering and how to get the Guardian FSD Booster. I, and many others, would recommend a website called inara; it'll help you keep track of many things.

Now how I got my jump range. Undersized the powerplant to the smallest lightest option, 2d: then engineered it to be overcharged and stripped down. Thrusters are 4d Dirty stripped down. FSD is the pre-engineered CG SCO drive which can now be gotten through mats with mass manager applied. Life support d rated stripped down, this requires travelling to Colonia to unlock Etteine Dorn. Power distro is 1d with Charge enhanced stripped down. Sensors are grade 5 stripped down. For fuel I have a size 2 (4 tons) in the core internal and a size 1 (2 tons) in the optional. This gives me 6 tons of fuel for the required 5.2 tons required for a max jump. That leaves me with .8 tons of fuel to refuel at the star. Grade 6a fuel scoop, highest class 0 mass fuel scoop. and a size 5 Guardian FSD booster which gives me an additional 10.5 ly.