As long as the relay is big enough you can run them all. Normally you'll find 30A relays in most parts stores or with the kits that come with the lights. Here's how to know how many amps you're drawing!! You have to use some maths. To figure out how many amps you draw you have to divide your watts by the voltage. Thats cause Volts x Amps drawn = Wattage. So the Hellas are 55W lights. You've got two of them . 110 / 13.8 = 7.97amps. If you have 4 55 watt lights you now have 220 / 13.8 = 15.94amps. Add two more and you've got 330 / 13.8 = 23.91amps. That's still under the 30amps so you're ok if the car is running.

Now think about those times you may turn the lights on when the motor isn't running. Instead of 13.8 volts you've got 12 or maybe even 11.8ish. 330 / 12 = 27.5amps still acceptable so I think you'll be just fine with the supplied 30A relay supplied with the lights. Just don't turn them on if your battery is getting low. Not only will it drain mighty fast but those wires/relays will be heating up. You could always wire two relays to come on with the same 2 wires if you were drawing more than 30.

Now for the wiring. I'm using 10 guage wire for my 4 lights. The kit supplies 12 or 14 gauge wire. That wiring is much too small to run 3 sets of lights. Go up to 10 or 8 guage.

I've got the 500FFs. They are definitely concentrated to one area as far as the light they throw. They throw a horizontal rectangular shaped slit of light. Not round like a spot. I'm going to add 2 more regular 500s to brighten up the surrounding area a bit more.

Have fun.