I had made new wirings/relay.. used almost 5 metres of 10-gauge (5.2mm2) wire from relays to headlight bulbs, some 14-gauge (2.5mm2) to connect factory headlights connectors to relays, 2 relays (one for low beams, one for high beams), 30A fuses and water proof fuse holders.
this url has just about all the info you need:
http://www.danielsternlighting.com/tech/relays/relays.html
teh cheap dodgy wiring/relay job
even dodgier relay mounting in engine bay