At 1000bb the cutoff plays chess: see flops in position with nut-potential hands, and let the early opener guess forever.
3-betting is nearly reserved for the top of the deck. Position and nut potential dictate everything else; offsuit broadways are mostly gone.
Good position against a strong range. Flatting dominates: you keep their dominated hands in and your speculative hands cheap.
Assumes a ~4bb open; 3-bet to ~3x the open in position, ~4x from the blinds — larger as stacks deepen.