It turns out I am on a 738 in First JFK-LAS. I chose 4D, the last row, which seems to be what the majority recommend. Delta has made many changes to this trip, but they have been schedule, not equipment changes. My traveling companions are flying out later on a 739ER and I have passed along the comments from here. On the return we are traveling together in C+ on a 739ER. Delta will not unblock row 10, I tried. Any C+ recommendations for the three of us?