The relays are mounted to a "bridge" I took out of a parts car using Bosch relay sockets I scavenged. The bridge mounted nicely with two slightly modified steel brackets to existing holes. This view is from the rear (camera over radiator) towards the grille. I have a simple cover made from the bottom of an anti-freeze jug which keeps some weather out. It would certainly have been more sophisticated and wiser, long term, to enclose all this stuff in a waterproof wiring box... but after three years it's still working well with no signs of corrosion.
The high beam relays (black) are 40 A units, the fog (blue) and low beams (grey) are 30 A. The silver one on the end is an SPDT 30 A relay and the red one is a 30 A normally closed relay, both for the "city" or ultra low beam function.
This photograph shows the three fuse block and its direct connection to the alternator output. One for each high beam and one for the low beams. One of the high beam fuses also powers the fog lights, since they are never on at the same time. The main feed is 8 gauge, with 10 gauge wires from the fuses to the relays. The fuses are either 30 or 40 A. Yes, it is mounted with two zip ties to the lower radiator hose! They are loose enough not to chafe, and the wire is pretty stiff, which keeps it all in place. There just didn't seem to be a nice easy place to bolt the thing down at the time. Someday...