But you're talking about ambient temperature, not the temperature of the fermenting beer, correct? Since yeast generate their own heat, and you're probably using a s#!%-ton of hops, I would go with the 60 degree spot. I know you're already done, but who cares if it takes a week or two longer to finish? Unless I'm mistaken, you were looking for a place to start fermentation, so if that stage takes a little longer, you will still dry-hop for the same amount of time, so don't have to worry about age affecting your hop character. If you're using the California or American ale yeast, it's pretty versatile and will just make a cleaner beer at a lower temperature. Just my 2 cents...