You can tow the flotilla with the San Pedro like Ben said and use the spare 2 points to upgrade Leon into El Duque for better speed and cargo.
I don’t see that as much of an upgrade since Leon has better cannons and a solid ability. Though I’ll always favor a ship like the Leon over a ship like the Duque. 🙂
@Mechavelli: Diablo being towed by the San Pedro would be an excellent deterrent and a good way to protect your most valuable ship. The Raton is pretty slow for towing Diablo, so she might have trouble getting the firepower into position and keeping up with the Leon or San Pedro. Though depending on the setup you could just plop the Diablo near important islands and run gold with the Raton too.
I think swapping the FPS to a helmsman on the Bloody Jewel would be a good idea. However, since you say you’re playing against newer players, I probably wouldn’t do that for a starter game since it makes the fleet more competitive. I think leaving it as-is would be cool, I like the fleet! I like how you’ve got at least 2 cargo open on every ship.