headlight relay wiring

Here's the situation: My snowplow headlight modules decided to go bad, and I am going to just wire up my own standard relays to do the same job.  However, it's been a while since I played with relays, and considering I need Hi and Low beam lights it might be tough.  I am going to give you what I have come up with so far, and if you guys see something wrong or an easier way to do please let me know:

Relay Configuration:

85 - Ground

The goal here is to use a rocker switch to activate the relay and shut down the vehicle headlight, and turn on the Plow Headlight.  My main problem is the high beam?  I can't figure out how to wire in the high beam?

Use a second relay.

87 of first relay to 30 of the new radio.  87A of the new relay to the low beams of snowplow.  87 to high beams of snowplow.  85 to ground.  86 to a high beam switch. 

I would think you would be able to hook the relay(s) up to a rocker switch like you proposed.

Then, wire pin 30 to the output of the low beam head light switch (basically to the stock lowbeams, switch side).  Wire pin 87A to the stock low beams (light side).  Wire Pin 87 to the plow low beams.

When the rocker switch is off the stock headlights will operate as normal.  Once you flick the rocker switch the plow headlights will operate just like the stock ones do (in regards to low/high beam).  This assumes that the plow lights are of similar size (wattage) as your stock lights.  If the plow lights are significantly larger run addional relays off of the 87 pin above that is capable of delivering the amount of power necesarry.