Thanks you guys! Well, about my school: I don't know if you would consider it "HUGE", but it is fairly large, and we have a somewhat large Greek system. MTSU has approx. 22,000 students. The mainly social Greeks include 7 NPC sororities, 12 IFC fraternities, 4 NPHC sororities, 4 NPHC fraternities, 1 local sorority (somehow they're now a member of our local Panhellenic Council... not sure how this works, though), and numerous Greek-lettered honors clubs, religious groups, and volunteer organizations.
I'm not so much worried about us not having enough PNMs (we had over 400 girls signed up last yr), I'm just concerned a little about (like sugar & spice said) the chance that some of the best PNMs could be girls who hadn't even considered, or even known about Greek Life prior to coming to college.
Anyhow, thanks for clearing up all of that for me!
Something I'm still wondering about, however, is how we're going to do our "Greek Week"? I suppose PNMs will have to come two weeks prior to the start of school for that? Annually, we have a Greek Week which includes a "Sorority Interest Meeting", "Meet the Greeks picnic", a "GreekFest", "Mud Volleyball", and several other things.