Embroidery Companion (a great book, by the way).
Only, I didn't take into account how tiny this gingham is -- at least sixteen squares per inch, when most chicken scratch is done on 1/4 inch or 1/8 inch gingham. I used just one strand of floss and spent a lot of time with the hoop just a few inches from my face. Three of Paulson's diamond motifs created too tiny a heart, so I expanded the design using this heart pattern (that site also has some info about this style of embroidery).
For the second heart I took the easy way out and just sewed on some pink seed beads:
The hearts, all sewn up: