I don't think it matters much whether you leave from Sale
or Walkers. Last time I made similar passage
I left from Sale.
I would take a course more or less NW until I caught the axis of the Gulf Stream and then alter course more northerly to keep the maximum boost for as long as possible, then cut back more westerly to make Savannah.
Of course watch the weather
and if things deteriorate or the winds shift to northerly try to get out of the Stream and closer to shore.
Speed of the stream will vary. Where it pinches between FL and the western Bahamas
can be 3-4 kts but further north as the stream spreads out this will drop to maybe 1-3 kts.