Your itinerary sounds like a lot of fun and you have a good amount of time. Depending on your desire to spend time in the French islands, a few alternates to this could be:

Start in Grenada and do a one way up to Martinique. A while ago I saw that DYC was offering some very good pricing for one-ways in that direction with drop offs in St. Lucia and Martinique as this likely helps them get the boats back to their starting bases after the "normal" one way charter heading south. At that time of year the winds should be more easterly so the northbound legs should not be too bad.

Another option could be to start in Guadeloupe and work down to Grenada via Dominica, Martinique, etc. If I had the time, this would be my preference as you should be off the wind the whole way with some good sailing and interesting places.

Either way there are plenty of places to hole up if there is a tropical wave coming though.

We will be in that area for 10 days around the same time doing a round trip from St. Vincent. Have a good trip