My 48v/12v Reducer setup plan

[sparty9955@yahoo.com]

Reducer setup plan;

1. 12g red wire from large bolt battery side of capacitor to pos intake wire with built in fuse on 48v voltage reducer.
2. 12g black wire from black yellow bullet wire behind battery 4 that connects directly to B- on controller to neg intake wire on 48v voltage reducer.
3. Yellow wire from 48v voltage reducer to blue wire at the switch (which I believe is the cold side/switched side).
4. Black 12g output wire from 48v voltage reducer to fuse block.
5. Red 12g output wire from 48v voltage reducer to fuse block.
6. All accessories wired to fuse block (radio, headlight/taillight, underbody LED lights).

I’m mounting the 6 panel fuse block in the battery compartment. The 48v reducer is being mounted up front under front cowl space on metal bracket. All wires being ran through dash and under floor mat in little grove with main harness to battery compartment.

Does anybody know what size amp fuses I should use in fuse block for Radio? Head/taillights? Underbody LEDs?

Also, should I include a 48v relay on this? If so, do I install it anywhere on the red wire from capacitor to red input wire on 48v voltage reducer.