I adlo first, its a good habit and makes it easier for the tank since you don't need to heal the first hit in a pull (and risk gaining aggro if the tank ain't fast enough) in a large pull I also cast an adlo and stoneskin otherwise during the large pull the tank will melt before he even finishes the pull since I need to wait for his aggro to build before spamming heals otherwise aggros on me.

Basically the tanks in his own right if he feels more comfortable knowing he won't be fighting the healer for aggro at first pull.