Think about your family first. As people have recommended above.. slap down a deposit if you can and hold a seat. St. Maartin is a beautiful island, but still.. you have to ask yourself if your kids will suffer in any way (tropical disease, education, friends) for your two years down there, plus God knows how your 3rd and 4th year rotations will turn out, where you'll be, and how you'll move your family with you (education, friends for your kids, stability).
Being a government brat myself and constantly on the move when I was a kid, I can say while I'm grateful for having been exposed to different cultures, I think I would've far appreciated havign a bit more stable childhood and friends. One moment I'd have to adapt to the British system, then back to American. Have to make new friends, then say goodbye.. it's a difficult life for a kid to move all the time.
So the best bet would be to wait for the DOs unless you can't.