One note.. I thought about soldering the relay in, but then decided against it in case it fails, replacing a relay at home if soldered would be a pain, it would be impossible out in the bush. So female crimp connectors are the best option. Labeling the wires/connectors with their corresponding numbers wouldn't be a bad idea either if you plan on carrying a spare relay and wanted the ability to change it out quickly.
Oh yeah.. and a big thanks to Kev for pointing out the 12v power source under the seat, it works perfectly for providing switched power to the relay.