For me, at the moment, the question of single or dual queues is the most important, so I'll add a few more pennies to the discussion . . .
FIRST -- if the new game programed mechanic means dual queues CANNOT be planet-side, then my strategy will likely always involve making one or more smaller planets exclusive factory worlds to produce capital ships for my empire. No doubt these will be resource draining worlds subsidized by the empire for the sake of the ships they produce for the empire and their sister worlds. Their individual planet wheel will always be set to total manufacturing, regardless of how the empire wheel will be set -- my "work around" the single queue condition.
NOW THEN -- based on this strategy, I will again support the idea of a "space-based capital ship construction platform," my version of EvilMaxWar's ship builder star base. I like the sci-fi "quasi-realism" that avoids issues like escaping a planet's atmosphere and gravity, etc.
1. This star base -- as I suggested in an earlier reply -- would be like the GC2 Terror Star, requiring a number of techs and specialized modules to be constructed before it could function as a ship building platform. Regular constructor modules could add weapons and defenses and fleet capacity like other star bases. In GC2, star bases are subsidized by the empire, so that would likely happen here.
2. By the time this base could begin building capital ships, it would achieve the status of an "artificial planet." Thus, it would have its own production wheel as any regular planet which could be set as if it was a planet.
3. As I said about the single queue mechanic with small planets only producing ships, these ship builder star bases would be subsidized by their empire. Thus, there is no need to have an extra production slider on the empire-wide resource allocation wheel. Remember, new colonies need to be subsidized until they produce economically for the empire, and there are no management issues there. These artificial planets will simply be permanently subsidized. They will grow in population as other colonies grow; they will receive resources from the entire empire; etc.
1. Planets keep one queue, and build whatever the leader wants, social projects or ships.
2. Artificial planets (ship builder star bases) will also have only one queue -- to build capital ships.
3. Still one empire-wide wheel to control how resources are directed, and still individual wheels for planets and these artificial planets, so no need for special sliders.
4. In times of war, leaders can quick-build more artificial planets to produce more war ships more quickly.
Again, others may have better ideas, but this is what fermented in my brain.