Between WHFB, KoW and Grimdark Future, I’ve tried various ways of storing armies and all of them had problems. Recently I’ve built up this box.
Its double corrugated with some 3D printed reinforcements and handles. Inside the box are two foamboard trays. Lining the bottom of those trays are Gridfinity plates. In the above pic you can see the grid with three trays sitting in.
A closeup of the trays. Boxes can be custom built online but then I used 3D builder to cut away parts of the side so your fingers can easily grip the unit bases. The unit bases are magnetized and you can see the steel plates that hold them onto the trays on the left. The idea is that for fiddly or delicate units you don’t have to reach down into the box and fit your fingers in tight spear filled space but can lift the trays out and then easily remove the units.
Here is the underside of a tray. you can see the squares that fit into the grid inside the foamboard trays. This one is actually cut in half because that allows Cav units to be fit in a bit more efficiently.
My elves fit into one of the two trays. Obviously I need to buy more.