I would go with the darker tones for the 'curve' pieces, to represent the waves. I would also use the single sash block (the basic one) and not the double sashed block. It is way more fluid looking and is the original intent of the pattern.
Pics for comparison, and, though not in the colors requested, the values depict waves and motion.
Top one is double sashed (looks very boxy)
Bottom one is single sashed except on the edges
Depending on how dear this old friend is, you could do one of the heart outlines in a slightly different shade from the others so it very subtly shows.