Put new rotors on 73 Swinger and pads are rubbing!?

I just got this car rolling, and went to change out a broken wheel stud and found a very worn rotor hidden behind some newer pads, so I ran to NAPA and bought 2 new rotors with pads and bearings and threw them all back together. I BARELY managed to get the caliper on, had to compress the C clamp as hard as i could till the piston was flush with the rubber boot. Took the clamp off, put the rattle plate and wheels back on, started the car up and pumped the breaks and the pads are still rubbing to where i can barely move the tire if i push it with my foot. Both tires are rubbing eqaully like this.
I was told the piston may not be retracting all the way, and i havent torn them apart yet, but I'm worried that NAPA sold me too thick of a rotor. They were made in Canada and have what looks like cooling fins on the side facing the motor (counter guy said it was the ABS style).
Does anyone know the maximum rotor thickness for a 73' dart? Each of the old ones look like one side was turned down half the width of the opposite side, I'm not sure if that was stock, or someone else ran into the same problem or if it was just turned down to smooth out some older damage.
If It is just the calipers giving me grief should i just buy a new pair? I do have minor damage on one piston boot, but no leaks.
Just how far is a piston supposed to push out? These seem to move out about a Quarter of an inch when I had my girlfriend push the breaks for me while i had the caliper off.