Relays and fuses
1) Do I put the fuse between the starter relay and the relay?
YES. A fuse/ breaker always goes as close to the source as possible
The headlight relays are rated for 30 amps, do I use 30 A fuses for the headlights ?
I'd say "it depends." If you are only running no14 wire to the headlights, or if the headlights don't draw anywhere near that much (stockers) then use a smaller fuse. I'd take a meter and measure the circuit amperage with the engine running and charging (above fast idle RPM) and see what it draws. You do want a lot of "headroom", though, on fuses for headlights. The LAST thing you want is for a fuse to blow "falsely" when you're tootin' down the dark road. IN FACT I would consider using a breaker instead of a fuse, just like the factory did.
the fan relay is rated for 16 amps (15 or 20?) for the fan?
That must not be much of a fan if it only draws 16 amps. I'd investigate to be sure that the relay is actually only rated at that, and that the fan draws less than that. Once again, what size were are you using to wire this up? Once again, I'd measure the system amperage. Turn the fan on several times, and check if your meter has a "peak hold" function to freeze the surge current. Motors generally draw a lot of current on startup, so if it runs at 16, it may actually need a larger fuse to handle startup current.
Also, mount fuses and breakers AWAY from engine heat. Heat lowers the amp rating on both
