Just my two cents as I am tinkering on one at the moment, too:
https://edsy.org/s/vaSjAzD
Its designed to require only a minimum of engineering, so there is definitely room for improvement there - but thats not the point. Lightweight everything and range goes up...kind of a no-brainer.
But I feel that jump range is, once you get over a certain "feelgood threshold" that lets you cover a good distance in a short time if the need arises (in my case thats about 70ly), not that relevant. As others have said before, you are doing efficent jumps most of the time, anyways.
In my opinion, after the "feelgood threshold" is fulfilled, two other factors are more important - scooping speed and heat. Regarding scooping, being trapped in an already explored system watching your tank getting filled is about as interesting as watching paint dry. Regarding heat, a low emissions PP paired with a ship with acceptable heat capacity (which the Phantom is) allows you to charge your FSD while still being in the scooping zone. There was a special term for this technique that escapes me right now...getting old I guess - anyways, it really raises your travelling speed away from charted space. Or back, if you really want to do that.
I have opted for a bigger SRV-Hangar to have a spare if I manage to drive under influence again and...well lets not reiterate that. Furthermore, a second AFMU allows you to repair each with the other, respectively, and keeps you on the neutron highway forever. The Thrusters and Shield are sufficient in my experience. As long as you keep the ship straight and (much like a plane) in a slow, shallow descent, any Thruster will keep you in the "air". And I had a pair if those stored, anyways. Just don't touch the downward thrust.
I always fly empty and synthesize limpets if the need arises, so a big cargo rack does not help much.
I guess every explorer has his own preferences here, however, perhaps you find some inspiration in my ramblings. See you in the black O7.