4, 6 & 7 (I don't own one, but has been guiding one around/helping it dock with lanes).
I like the idea of a jumping-only huge can, that will take some time to unload by transports, and thus provide a target for pierats for a brief window of time, while requiring a group effort to use. I would like incentives for jumpgroups to jump with a barge, a handful of whales to unload it and escorts to keep the barge safe, and I think a weak-ish barge that is unable to dock with anything would provide that incentive - perhaps lower the hull and put on a larger shield. Faster turning (perhaps only vertical if possible) to offset the slamming/lackluster physics.
And make sure there is fair and equal access to the ship, i.e. provide bases where it is sold or make it possible to construct on player bases.