I have a fully IO'd Kin/EA, i would usually start with BU, Concentrated Strike, BU, Assassin's strike, Concentrated Strike, BU. Often i would loop that combo several times for 3-4 BUs. Since i have the Gaussian IO, sometimes it will end up with a 3 stack BU. With perma hasten and assassin's mark, you would be clicking the BU button like a maniac.