The Park book might already have a similar tip, since the instructions on the Park web site do (they recommend a piece of rubber band), but I just toed my pads with little rings cut from an old tube. Better than a business card or a coin, I think because you just slip them over the end and don't have to hold them in place.
My approach to your problem would be similar to what's been said: loosen up a lot, wiggle everything around a bit (maybe twist the concave/convex washers in different directions so they can't sit exactly the way they were doing before), then hold the pad against the rim, put tension on the cable (I tie something around the lever. there might be a more sensible way), and tighten.