After Galton, anybody commanding a fleet (or two) going after Darius should keep in mind that:
1) There are still warships that nobody has been able to track and even if they did not appear to engage at Galton, they are still a massive threat.
2) The grazer weapons that have been used by the Alignment are very effective- when they can sneak up on you. So more work needs to be done to try and figure out how to detect them as well as this "invisible" warships.
3) The Alignment has a nasty habit of trying to break off any trail or destroying as much physical evidence of their operations. That includes obliterating buildings or stations with implanted nuclear weapons, installing software self-destruct routines (not under the operators control) into ships, and using nanites to kill captured agents including their own personal.
4) They have been very inventive in their development of systems, particularly weapons systems and there will be nasty surprises.
If you are going to take on Darius or probably just about any Alignment system, perhaps you might think in terms of making some very large MDM missiles and then launching (with strap on boosters ) from a long way out from the hyper limit and slam them in those massive (or any other) orbital forts as a terrifying % of C and use kinetic energy to obliterate them. Give these are the people who ran Oyster Bay, I would't worry any about the debris hitting anything else in the system including planets.
The reason Bloodhound could ID Galton - from as far out as they stopped creeping up on it- as inhabited and had a massive infrastructure was by the amount of electromagnet radiation and other emissions pouring off it. That emissions travel a long way, it just takes a lot of time. The amount of energy etc being picked up by Bloodhound let them calculate how much was being used. And the system was being used as an arms foundry.
Darius will also be equally noisy since they are running a large population, building giant starships in orbit and running (how can the not) massive resource processing and materials fabrication plants. And the communications are unlikely to all be wisper lasers.....there will be a lots of people and equipment making a lot of noise passing information and speech around back and forth in-system.
Darius appears to have kept Galton as a compartmented secret from the vast majority of the Darius population (at least as well as Bolthole has been) so why isn't it reasonable that there is at least one other secret base for the Alignment? They have done a lot of that both on planets (like Mesa) and also with Galton and Darius. Lets not forget the RF- another master web of misdirection and hiding in plain sight of what is/was intended as the point of hope for systems with the fall and destruction of the SL as the most powerful human force in the galaxy while injecting Alignment Philosophy into the surveyors.
They just can't stop doing that.....
