I dry hop for three days at room temps - usually mid or low 60s as it's in the basement. I suspend a pre-boiled mesh bag with hops and a stainless steel weight halfway into the keg with unflavored dental floss. If I am using more than 2 oz, I'll use two bags so all the hops get contact with the beer.
Twice a day I will connect CO2 to the liquid out post to agitate the beer and hopefully swirl the bag around.