All dates are for at least 2 passengers. Didn't do extensive searching after that, but I randomly entered 9 passengers and got the same price for selected dates. Cheapest redemption to this location, I believe... Checked a few other Caribbean destinations and just got 17.5/15k.
10K Sample dates JFK-PLS (non-stop and some with stop in ATL):
Dec. 29 - Jan 1
Jan. 3 - Jan 13
Jan. 16 - 20
Jan. 23 - 27
Jan. 29 - Feb. 4
Feb. 7 - 9
Smattering of days throughout the rest of Feb. and early March. Some stop or non-stop.
10K Sample dates PLS-JFK (same as above):
Dec. 27 - 29
Jan. 11 - 17
Jan. 20 - 22
Jan. 25 - 26
Feb. 2 - 7
Smattering of days throughout the rest of Feb. and early March. Some stop or non-stop.
I have Delta Skymiles CC, but was not signed in.