When I was still working, mine were always stored vertically. The longest 3 stood on end, on a little shop made shelf. The shorter ones all hung from trim-head screws.
Now that they are all home, I don't have the ceiling height for the 3000, so it now sits in the very top French cleat. It stands vertically, splinter strip up. That makes the logo upside down, which bothers my head a bit. It's not exactly ideal to retrieve either. It will get moved eventually. There is enough head room in the next room, but that's not ready yet.