I have a lot of stones, and I think the main consideration is how long they take to dry, which can vary greatly.
I find that coarser grits take longer to dry than fine grits from the same producer. A Shapton 12K may dry in 15 minutes, whereas a 220 may take an hour. The harder, ceramic based stones dry very quickly overall.
Stones that create mud can take forever to dry- King, Norton, Suehiro. I have a 1K King Hyper that takes about a week to fully dry.
My storage solution was very cheap and effective- dollar store plastic shoe boxes. They can hold from 2-4 larger stones, or more than a dozen thin ones. After sharpening, I air the stones out by placing them in the box at a 45 degree angle. When they're dry, I close up the boxes and stack them in a drawer. Works perfectly.
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