Hi there,
I'm planning a similar trip next year (From Boston to
Spain via the Azores). Sept/October is perhaps not a great time to be in that area since it is still
hurricane season. I'm planning on leaving late May/beginning June to avoid
winter gales and hopefully before the
hurricane season starts.
I would recommend looking through John Kretschmer's website
https://johnkretschmersailing.com/
and try to join his webinars. He just did a two part series on Atlantic crossings, with the first part focusing on West to East, and the second part East to West. Totally worth it.
Good luck,