how would i summon an armor stand holding out his hands facing east in 1.11
Solution 1:
You need the Rotation tag:
/summon armor_stand ~ ~ ~ {Rotation:[*value Y*,*value X*],Pose:{RightArm:[270f,0f,0f],LeftArm:[270f,0f,0f]},ShowArms:1}
The rotation values define the rotation on the X and Y axis (example: Rotation:[270f,0f]).