I had a look at the table. I noticed that drying time for soaking stones is often quoted as "at least a day". Unless you have exact information - I would rather write "several days". For the Gesshin 400 and 2000 where I have the data I would write 3-6 days (it was 4-5 in not too humid environment). In fact - if you know how much water the stone absorbed, you could reasonably well calculate how long it will take to dry since the surface of the stone for most stones similar (unless the stone is over-sized, than it may take longer).