I would be careful about the marina choice. Port St Louis marina would be first choice; it's the safest in Grenada. Then, only if they gave a double berth between two finger piers. You could then lash her down properly before leaving to meet the insurance
requirements, this is because they might promise it, but I bet they won't be able to secure her the day before one hits. I would only do this before 3rd wk July, after then the risks rise massively.
On the hard you have to pay for a cradle wherever you are. Trinidad is a bit cheaper, better for working on the hard and certainly safer for the boat and would be my choice. A nice day sail there.
If you pick Grenada, then ensure the boats next to you are in cradles too. It is not an insurance requirement, but it should be.