Thanks nsurit, Solarize, Bob, rw, Lopaka and Photographs for the advice.
The problem is that I have exams (semester is ending) + projects to complete, so the mats (4 ply) I'll be ordering will be precut. I'm looking towards an 11x14 with a 6x9 window; the outer edges all being equal at 2 1/2 inches, so no optical centering for me.
Since I'll be choosing to print at 6x9, I'll cut it with maybe an inch to spare all around making it 7x10. That'll give me about one inch to place paper corners on it and affix it to the mounting board (and not Foamcore as Jerome suggested).
Afterwards, they'll be placed into a portfolio case; which I assume will be just a case. Similar to the boxy plastic three ring negative binders that we photo kids carry.
Does this sound alright to you? Or am I missing something here? :confused: