Sorry Bill (and others), I didn't intend for my numbers to be used literally. I just pulled some numbers out of my a$$ to illustrate the point. You're right that steady-state the loads will be well be below what the circuit is wired and fused for. You did it right looking up the ratings for each of your components.Looks like you are adding the fuse amp ratings. The real loads are much smaller than the fuse ratings. Fuse amp ratings are based on the wire size being used so that a short circuit blows the fuse rather than start the wires on fire. Bright headlights are usually 55 to 60 watts which is about 5 amps each. We use 16 ga wire which is good for 20 amps. Hence, a 20 amp fuse.
One thing about the high amp alternators is that they don't always put out their full rated amps at low speed. Also, the one wire units have to be turned up to high RPM's on start up to get them charging.
Mike