I actually bought a moisture gauge from ebay. It is an amazing one and has a range from 0% to 60% in tenths of a percent (ie. 11.3%). Typically, I soak my bowls for about 2 hours. If it is a really really dense wood, like Eucaliptyis (?spelling?), then I double the soak time. Basically, when I no longer see bubbles coming up from the wood, I consider it soaked enough. I then let it air dry for about an hour, then I wrap the outside of the bowl with part of a grocery bag. During the course of the next week, I take readings on the bowl with my moisture tester. The last bowl I did was Box Elder and it started out at 21.3% moisture. It jumped down by about 2-3% per day. The day before I turned it, it was at 11.1%. The next day it was at 0%. I finial turned and finished it that night. It was 5 days after I did the alcohol soak on it. I also did some pen blanks in this manner. It worked great for them as well.
Wade