I do my experimenting, butI also do some additional research outside of google analytics. I use google trends, google insights, ebay pulse, etc. From this I found that Australia should be one of the biggest viewers of my site. Currently, they are not so I'm experimenting to see if I list at say midnight EST would it increase my views in Australia. Another thing I found was that the UK ranks first in searching for French vintage, but the the AU ranks first in searching for French country. I use this information to determine what items I'm going to list at what time point.