In the winter, the prevailing wind is typically east to northeast. In the summer time is is east to southeast. I'd give it a try. You may be close hauled or have to motor a bit, especially in the lee of Grenada. With 11 days you have plenty of time to get to SVG. You could motor from St. George's to Blue Lagoon in a bit more than 12 hours. In the winter, this would be a slog..