'73 Swinger brake drag

Well like I said, the calipers are brand new and the pistons are pushed in until they're flush, so I don't think that's it.
The smaller front of the master cylinder (marked R) goes into the bottom right on the proportioning valve, and the bigger rear (marked F) goes into the top of it. That's correct according to the diagram.
Is there not supposed to be ANY gap between the pads and rotors? How do you judge if they're dragging or not?