EF or the EXP desk are the best places to look for C inventory.
I have recently had some discussion with EF over the AA C inventory issue. I REALLY wish they had the ability (apparently they don't) to show all flights for a given date for a given city pair. Often you get only two times (depending upon what time you feed it), even when there are 5 or 6 flights flown in a day. And furthermore, when AA sees two C0s in a row, it quites when it gets to the third C0. A real hassle, in my opinion.
Now, time for a question. if you are Platinum, does EF ALWAYS show you all the C inventory available to you? And if you are EXP, does the EXP desk fairly consistently have enhanced inventory over what EF says?