Introductory/my current issue

[YourWifesBox]

How’s it going fellas(and gals). My names Joseph, i own a 93 240sx, 94 civic, and a 83 Volvo wagon(HELL YEAH BROTHER). Currently swapping a sr20det into the s-chassis. Little background of the car; i traded a pickup for it and did the deal at night. Horrible decision. Brought it home, found the misfire was a lot worse than i thought. Pulled the head and the cyl. Walls were PITTED to hell. Trashed the motor and got a sr.

Now the car had a s14 ka in it and the moron who put it in left none of the original wiring besides the taillights wires. So everything got hard wired with switches. I’m fairly sound when it comes to mechanics but this wiring has been a train wreck for me. Battery is in the back with a battery shut up at the dash basically as a “key” then goes to the starter. Now I will be the first to admit i don’t understand a thing about wiring and this is where i need help.

I got a wiring specialties pro harness with a patch harness. Got the harness on but need to know. Excuse my lack of common sense for basic wiring.
1. The harness came with a charge line that’s for the starter to the alt., is that supplying the alt with 12v and the sense line is what goes back to the battery to charge? If so I’ll have to splice in the harness to run sense line back, correct? If so what gauge you recommend for that.
2. When it comes to my switch panel, am i better off buying a ez wiring kit and running my acc. Threw that then to the switches? Or any better recommendations.
3. My fuel pump needs wiring up, i have a basic idea on how to but when running it to a switch what is the process of that.

I do have an entire chassis harness i got out a junked 240 but would like to run as little as wires as possible and not have to fish all that back threw especially since I’m not using the good ole electric seatbelts, stereo system, ac/heat, and anything else practically. Besides lights, wipers, fans, and fuel pump(obvi) but would still like to have a decent wiring setup and not homedepots thhn wiring all threw the car. I have an apexi boost controller and safc that’ll need wiring which is pretty straight forward. Excuse my mumbling on, just getting as much as i can out to help you get my situation. I have some other things that need working out but for now that’ll be some help. Again my apologies for the stupidity of this, the searching has just gone to long and found diagrams that help but haven’t found the answers I’m necessarily looking for. Help would be great. Ignorance is also welcomed as i know it’ll come. Thanks guys.