Originally Posted by No_0ne
The brackets do mount on the bottom of the spar, however from the pics it looks like you might have these reversed, as the "slanted" portion of the bracket goes on the inboard side. Admittedly, it's hard to tell the exact orientation due to the viewing angle of the pics you posted.
No, the slanted portion goes on the outboard side.
It is meant to match up with the tapper angle of the longeron on each side.
And yes, the brackets are located on the bottom.