We did the Iberia flight many times, also Condor. Suggest staying at the airport hotel, especially if your Tortola tickets are separate. You may need that cushion for late arrival from Europe. Also check Seaborne, because their early morning flights can be much cheaper.
We are experimenting with overnighting at the airport hotel in December, even though we could have made it the same night. It's so much easier to arrive during daylight with time to provision.
Try dinner at the Metropole in San Juan; a cheap cab ride and good Cuban food.
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