I went ahead and booked with them. The flight is even scheduled to leave at a convenient 11:30. We don't have to get up early and should still get to Tortola by around lunch.

We have a sleepaboard the day we arrive in Tortola, so assuming everything goes as planned will have an afternoon to kill so a delay won't really hurt us, as long as the flight eventually gets there. I'm going to use the funds I save vs. air charter to upgrade us to 1st class on the way home.