Grenadines in October

[RonK]

We are a couple who are planning a bareboat charter in the Caribbean in mid October. We're experienced Pacific sailors but have had little experience in the Caribbean. We're considering a 1-way charter picking up in St Lucia (moorings) or St Vincent (Horizon) and dropping off in Grenada to avoid having to beat back to base. Our questions are:
1. What are the likely prevailing winds during October (assuming no hurricane)? In winter the trades are from the NE but in the summer months, apparently they shift to more southerly, so we could find ourselves sailing to weather heading south.
2. Given the above, is it worth it to do the 1-way or just do a round trip from either base?
3. Any experience with Moorings vs Horizon? Other charters operators in the region?