ok folks here's my current spec
http://www.swtor-spy.com/skill-tree-calculator/sentinel/18/?build=002300010000000000000000000003203220212012200120023001002020000000000000000000000000
first off i have NO interest in PVP, and to my mind the constant damage done by me using this spec and rotation i have no problem keeping focus , putting out high consistent damage..
my rotation consists of force leap into the fight, zealous strike, strikex2 (this give me a full focus, then use rotation of blade storm precision slash, master strike, and cauterize , filling in with blade rush/zealous strike/strike as needed for cool down. once 30 stack of centering is built i use the 6 strikes of blade rush with the extra aturu form strike .