(Correction after tests) I prefered
Deep Charge as experimental effects, but Mass Manager seems to give slightly better results. This fit is that of the Fuel Rats so I'm not surprised that they use this special effect.
A 4A FSD weights the same (10t) than a 4E and is lighter than a 4B by 6 tons, it offers a much longer range than both, Optimal Mass etc, so there is little advantage in fitting a lower grade FSD on a ship unless your power supply is low...
FSD Specifications
Deep Charge increase jump range significantly but as we can see, Mass Manager does even better, you also can fit the largest Fuel scoop possible on your ship, then reduce the fuel tank size by half from stock, this will save tank and fuel weight.
On the Dolphin, I wouldn't hesitate to fit a 5A Fuel Scoop and play around with the other 2 size 4 Internal compartment for whatever you need, I'm thinking about a 4H Guardian FSD booster for example... For the shield a size 3 or even engineered 2 would be enough for the kind of work you wanna do with it.
Here is the Krait with the exact same fit appart for the Experimental effect, Mass Manager full image and Deep Charge below. I had two 5A Frame Shift Drive, one with Thermal Spread, all I had to do is to go to Khun and change the Experimental effect to test them back to back.
View attachment 329147
View attachment 329148
One thing I particularly apreciate with my Krait is the fact that I never, ever have to slow down or wait for the fuel scoop to fill my tank, it's a 6A Fuel Scoop and 4C fuel tank reduced from 5C, it is fitted on the only size 6 Internal compartment, most of the time, I'm full from a 60LY+ jump before I have the next target in line of sight, it is a clear advantage for fast traveling and it doesn't overheat.
I figured that the larger fuel tanks (or additional which I use sometimes) are better for ships which are not equiped with a fuel scoop, but also that a small fuel scoop isn't necessarily a gain, your ship can take the heat with time, the faster the scoop, the less likely to overheat.