As far as there being seats available on the later flights, I really don't think that will be a problem. And we generally just book the cheapest seats on the plane. However, we are thinking about booking Delta Comfort for the trip home, if we have enough miles to do it, so that could be a factor. I assume without knowing that there will be Delta Comfort seats available on both legs of the flight, not just the SXM to Atlanta leg. Guess I need to look at seating for second flight..