I know a Siebel-trained commercial brewer who makes great beer. He told me that he likes to dry-hop when the beer is closer to room temperature and his reason was that dry-hopping in cold beer brought out vegetal flavors of the hops. I have mentioned this to other brewers who say that they will leave a hop bag in a cold keg the entire time the beer is served without issue so some of this may come down to personal preference. I typically add DHs to the beer after fermentation is complete and the beer is around basement temps and I do the 3-4 day thing. It seems like plenty of time to get good hop character. I will make pale ales with Amarillo, Citra, Simcoe, etc. and also make pale ales where the DH consists of more neutral hops like Liberty, Ultra, Santiam, Sterling, etc.