You'll need a 15mm wrench.
I'd skip the A530s. I hear the platform side isn't very grippy, so unless you are going to be wearing your SPD shoes 95% you'll want a little more traction between the pedal and the shoe.
Just get the M324. Yes, they are heavy. But both sides of the pedal are useful in all but the wettest conditions. And as far as weight goes - you ride a steel bike and are asking in the commuting forum. It doesn't really matter much in the grand scheme of things.