As for how I store the army. I'm a fan of the KR Multicase and everything in the main army photo below, plus more (Highlanders, Roughriders) live in KR cases and the 4 case bag.
KR do shallow trays with space for 50 models. I'm not too sure that Space Marine type models would like this but you can fit four of these in one case. With a bit of squeezing you can fit 3 of these 50 model trays with KR's Heavy Weapon team tray (shown in the 4th photo) in one case. In all I can fit 150 infantry and 16 Heavy teams in one case.
The Armoured Fist Platoon (45 figures) get a case to themselves consisting of 3 x Chimera/ Leman Russ trays with two 25-figure trays. The 5 spaces left over get used by the Commissars. Note that I do have one space left over for a further vehicle in this case.
Case 3 contains the Sentinels (1 spare space) and the Ogryns. In the other slots of the left hand tray are fifteen Rough Riders. The remaining Mortar Squad, Preachers and the Curious Constructs Artillery crew reside in the infantry tray that fits on top.
The final case has the Leman Russ tanks and two Chimeras. In the two trays that fit on top of this live the Highlanders and any other bits and bobs.
And the bag that takes them all! As this is a primarily metal army the bag does have a bit of heft to it.