It will just depend on the tailwind. I've done Nassau-Heathrow and landed with over 5000 pounds and it's only an extra 90 miles or so from South Florida. You can always tank up, launch, and keep close watch on the fuel. Around 30 West, if you don't like what the box says, call your handler on the batphone and arrange a stop in Shannon. Westbound, you'll probably have to stop every time.