Best way to upgrade with Delta

I paid $1150 for economy comfort from LAX to HNL (return) for December. Business Class showing as $2800 atm, is it likely to come down nearer the time or should I see what they offer at the airport? There are 7 passengers.

Personally, with it being a domestic flight, I'd save the money and just remember to take some food on the flight. I'd very much doubt it'll come down by the way.