Use any length or width of paper to make quilled hearts. I make two loose circles, pinch into teardrop shapes and glue together at the sides.
When I make hearts using 12-inch (30.5 cm) lengths or longer, I like to make eccentric loose circles before shaping into teardrops. (It is not necessary, but I think it makes a more uniform shape for the heart.)
To make an eccentric circle, use a loose circle and bring the center to the edge using tweezers. Add a dab of glue under the loose circle at the edge to hold the eccentric shape. Allow to dry before pinching into a teardrop.
To make a lopsided heart into a shaped heart, slightly curl the point around a slotted tool handle or 1/4-inch dowel.