It took a couple posts for the original question to come into focus, but if I read it correctly, you were asking if the angle that the RR make to the frame as they extend forward from it to attach to the axle batwing should be accounted for with the mounting position of the bracket on the frame so that the heim end is straight, or with the bracket straight on the frame and the angle accounted for with the Heim joint.
I've always seen the bracket straight on the frame and the angle in the Heim joint, but it's probably more for aesthetics than any engineering advantage, especially in setups where the angle is only a few degrees.