My vision of the DA Legion organisation.
The Rock is the home of the DA, it's the amiral ship of Azreal, but no compagny are base on it, they are just visitor. It's the home of the inner circle, reclusiam, archive, forge, etc the head structure of the chapter is on the rock.
Other chapter have a battlebarge or fortress monastery similar to a Ramilies starfort as a main base of operation that act like the rock.
Each Company have a strike cruiser assign to it. On each strike cruiser you have everything a company need , and each have a squad of Deathwing and a squad of Ravenwing attach to them.
On normal operation, a Master have acces to his company and as need, the Deathwing and Ravenwing squad attach to his compagny. This will be enought for 90% the the task they need to accomplish. The reserve compagny, Ravenwing and Deathwing will not act alone, but will replace lose as need on the battle company (3-5).
Big opperation is the same but you have a battle barge add to the force, A master will be assign to it and the battle compagny will move inside, the strike cruiser of the compagny assign will stay at the rock for repair/maintenance during the major opperation.
In the rare occasion a single compagny or battle barge is not able to accomplish a task alone, it call for help and this is where the full might of the DA is unleash.The rock move into position, all ravenwing and deathwing squad are call back and come under control of the respective grand master.
We will soon learn more about the other wing and if they can be adapt to 40k or if they stay relic from the past.
The other wing are so specific i don't see a use for them outside of narative play. The Ironwing is probably the easier to implement with only Dreadnought, Tank and techmarine. Same for Dreadwing, just get all your special/heavy weapon in your collection, add 1 damage to all weapon and on wound roll of 6 mortal wound, call it Dreadwing protocol and have fun destroying your opponent!