what ashraf said is that he liked the way you had it before....understandably so. My suggestions are purely for keeping efficiency in mind. You will yield better results with my suggestions, I guarantee it. With regards to airflow in the case, you also have to remember that the PSU will provide circulation from the bottom as well. So i wouldnt worry about dead spots, but a little port hole opening definitely wouldn't hurt. But keep in mind that having more exhaust than intake is a good thing because you want negative pressure inside you case.
On another note, instead of a full cover block for your GPU's i would suggest running die blocks only, you'll get better temps and you're memory will not suffer either as long as you put sinks on them.

