14 gauge wire is more than sufficient, It will handle 15-20 amps. Your wiring is sound enough to make the most picky electician jealous.
As far as the relay goes, If you have a good light switch with clean contacts, I don't really see any advantage. Typically, you would only use them for a high demand load.
One option, would be to run an 8 volt battery, that would guarantee everything to be brighter.
Last edited by Whitedog; 01/15/2014 4:29 PM.
