There are humps and rises in deeper water off Key Large, Islamorada and Marathon that are beyond the shallower humps that hold AJs and tuna in 400 to 700 feet.
If you look at a good bathrymetric chart you may be able to ID some good spots in 900 to 1,700'.
In the 1980's, I knew a guy who fished out of Garden Cove Marina in Key Largo and he would run straight south off Molasses to 1,600 feet and drift well into the night to north of Pacific/Triumph and then run back to Garden Cove, and would pretty regularly catch nice swords. So, they have to be there.
Good luc
k!!
Juan