If you're only going to run the 100w lights listed then a 20 amp fuse should be fine...100w x2 @ 14.5V = 13.8 total amps. Just make sure you use good solid connections and if you're using push on spade connections such as at the relay or barrel connectors on the wiring put a dab of dielectric grease on the bare wire ends first to keep any corrosion down.

 

yeah i will be using spade terminals but from the lights to the wiring i will be soldering everything, heat shrinking and looming it all up.

 

REV... yeah that was an old diagram, I have since re wired everything. The diagram you have is what i have now. A fuse for just the switch and a fuse for the lights(fogs now)