It’s fairly trivial to clean up the game in a way so the components don’t spill around. First, ditch any vac-formed insert or at least don’t rely on it to ‘hold’ anything. Then basically just pick whichever edge will become the ‘bottom’ on the shelf and stack all the components against it. Start with the heavier things like decks of cards on bottom and lighter bags of tokens on top. A full shelf allows games to hold their neighbors closed. When taking a game from the shelf you can rotate a neighbor on its Y-axis fill the gap and press against the other boxes (if needed). For particularly troublesome games, silicone x-bands are a good option. (edit) Perhaps I should clarify that we store all components in small ziplocs or food storage containers.

My main grip with horizontal storage are the hassle getting games in and out of the stack. There’s also the issue of dishing and split corners from the weight of the boxes on top pressing on the boxes below. And, if they’re stacked ziggurat style, then it’s not efficiently using all the storage space available.

Super excited for the concept and extending the COIN system to more settings! I’ll probably try to play some async VASSAL games, but I’ve had to limit myself from buying any more IRL COIN games. They’re just too difficult to get to the table in my situation.