I think the four holes on card (a) are too close togethor; my FX 5900 has four holes as well, but they're too close togethor and I have to use the two hole hold down.
why dont you email them yourself? If you had when you posted the question, you would have your answer by now, I have even given you a direct email in my post.
Becuase im the helpful sort, Dano emailed me and said no, that will not work, you need to use the 2 hole bracket, not the 4 hold acrylic bracket. SO there ya go, you cant use it!
Chris
Cut and paste:
Chris,
The two hole mount is what is needed, not the 4 hole acrylic bracket.