Volts * Amps = Watts
so....55 watts at 12v = 4.6 amps (round numbers)
In reality, you'll be running at closer to 14.4v with the alternator charging, but it's simpler to do the math at 12v.
You would want to wire the lights in parallel, so the current draw (amps) would add. 4 lights x 4.6 amps ea = 18.4 amps.
The catch here is I don't know what the s-pod switches are rated for. They look a lot like generic Carling switches we use in the marine industry which are typically rated about 20 amps at 12v. ASSUMING (!!) the s-pod is the same, you'd be safe but near the rated limit. A relay wouldn't be a bad idea.
The only other thing to consider is wire gauge. I'd suggest going with 12 gauge given the likely round-trip wiring length (bat pos to fuse to switch to all lights to ground); that should keep voltage drops down to 10% or less up to about 40'.