jpch - 1:04 pm on Nov 8, 2013 (gmt 0)
I dunno how much traffic you get, but I'd probably leave it at least a few days to a week.
Enough traffic (80,000 plus page views)during the 40 hours that the test was running to reinforce what I was pretty sure all my other testing over the years had already proved. On my desktop test there was a 18% difference in RPM and on mobile it was worse...70% lower RPM. With numbers like that I'm not waiting around for G's Confidence Score to appear...which they said would occur around the 24 hour mark.