I've tried positioning both brackets around the WX 9100. The only position it make sense is for the cutout in the bracket to fit where the power cables go into the WX 9100. The screw holes in the bracket ALMOST line up with the holes on the back of the card. The way the bigger bracket has the "handle" attachment screwed it, it wouldn't allow the thickness of the card to fit flush.
For a $1500+ GPU card, the documentation leaves a lot to be desired.
P.S. There is no mention of what the top black port is for either.