The 15 - 20 kts (NW to NNW) that you're hoping for are currently 20 to 40 miles offshore
....40 miles ENE of St. Aug and 20 miles E of Cape Canaveral, bouys are reporting 15 -20 kts, from NW (310* to 330* True)
I realize that you do not wish to buck the Stream, but the Stream's core
axis is currenly east of 80* W, with about 1.5 - 1.75 kts flowing North....
So, if you head
a bit farther off, without going east of 80* 20', you should pick up better wind, without much (if any) extra adverse cuurent....
According to NOAA's reports from this morning, the WESTERN wall of the Stream is approx:
42 NAUTICAL MILES EAST OF PONCE INLET.
29 NAUTICAL MILES EAST OF PORT CANAVERAL.
28 NAUTICAL MILES EAST OF SEBASTIAN INLET.
15 NAUTICAL MILES EAST OF FORT PIERCE INLET.
10 NAUTICAL MILES EAST OF SAINT LUCIE INLET.
Staying west of the line, made by these points, should keep you out of any major adverse current
But, heading out farther than your present position should result in much better winds...