I also am looking forward to an SVI trip at some point. I can not provide any direct knowledge or help except that your best chartering locations are Fajardo, San Juan and CYOA in St. Thomas, unless you have a more than 10 days to charter, in which case you could probably work your way over in a boat from the BVI.

The cruising guide linked below, which someone posted here previously, has a great deal of information for you to look through.

http://freecruisingguides.com/puerto-rico/