Serendipity Streams is dominant to Double Odyssey Peace.
SerendipityStream>DoubleOdyPeace
The proof is straightforward: I paired a SerenStreams cat (Gwenaelle) with a Double Ody Peace cat (Southwell). They produced a cat showing Seren Streams (Iona). When paired with a cat showing Dry Olive (Qwaz) - which is known to be recessive to both of the other eyes, it pulls Iona's hidden out from under: the Double Odyssey Peace.
This PLACES Serendipity Streams above Double Odyssey Peace and below Tranquility.