[X] Adjust the design for a second deflector and longer nacelles. (Industry 9 -> Industry 11)
Aside logistics benefits, this also lets us get started on the more advanced technical paradigm. We have to get started on offset double-hulls at some point and it might as well be now.
[X] Adjust the design for a second deflector and longer nacelles. (Industry 9 -> Industry 11)
The Zheng He gains a deck and some height, as well as some extra bulk from the longer nacelles. Rather than design a new geometry from scratch you simply duplicate the nacelles from the higher-mass Stingray, which you already have the manufacturing process for all figured out. As the result the Zheng He will be able to cruise at warp 2.5 but reach her maximum at 2.7. You don't think running away from aggressive ships was ever on the cards, but you might eat your words if they get refitted with the Warp 5 engine and they're suddenly struggling to hit Warp 4.5.
In any case, the warp drive is well and truly decided and done by this point. That leaves the impulse engines and primary armament. Given how the two are likely to be intertwined, you consider the options. The new impulse engines are not only more compact but also more powerful than the reaction thrusters that they are replacing, but the manufacturing overhead is double that of their predecessors. Mounting two to the aft of the cargo section would make a surprisingly manoeuvrable ship, which would let you risk focusing its armament forward into a single powerful firing arc. Relatively speaking, and assuming the thrusters perform as promised.
Alternatively a single reaction thruster would give her basic sublight power, but given the minimal likelihood of being able shake an aggressive ship on her tail it would necessitate an aft phase cannon be installed. Despite being cheaper it would come at a tactical loss, since she could only have one cannon on target at any time. But these are the kind of decisions you have to make, figuring out which you think would benefit the Zheng He more in the long run. Powerful if it can stay on target, or a reliably available deterrence?
[ ] Two Impulse Thrusters (Prototype), Two Forward Phase Cannons (11 Industry -> 19 Industry)
[ ] One Reaction Thruster, One Forward Cannon, One Aft (11 Industry -> 16 Industry)
The first idea sounds cool, but this is a cargo ship, it borderline engaging in dogfights and turning to keep the threat in it's line of fire doesn't really line up for me.