Im looking at a list right now, a list of what I possess for each of the three battle companies. Not included on this list is all the extra "fun" stuff. This is commanders, chaplains, Tac, Assault, Dev squads, and dreadnoughts. You know what Im noticing by looking at this list? Codex Chapters all look the same on paper. Seeing as my plan is three battle companies from different Chapters, I should work to emphasise the differences in the organization, as well as the color schemes.
Lets start with the one with the most information available: The Imperial Fists. Siege masters, stubborn as me on a cold morning, and a real hatred for the Iron Warriors. So, got some stuff to work with then. Im thinking that the Imperial Fists will be having more Dreadnoughts then the other two, possibly more then them combined. That will help show that these guys have been around for thousands of years longer then the other two chapters. Im also going to keep them loaded for anti-MEQ and anti-tank combat, since they are hunting the Iron Warriors.
The Red Scorpions are fanatical about remaining true to the Codex, and their own genetic purity. Im thinking these guys will be lined up to take on all, in true Codex fashion, being specialised by not being specialised.
Information on the Marines Errant is scarce, most significant is that they served alongside the Red Scorpions during the Badab War, and that most of their gene-seed was stolen by Huron Blackheart recently. From what I remember, he did it by creating many smaller conflicts that scattered their forces far and wide. Not quite sure how I want to set these guys up, but Im seriously thinking of taking biker squads instead of jump pack assault squads. I also think Im going to point their gear choices towards anti-infantry, with an eye towards Orks and IG...