where can I find what the total volume of the MOC was?

I have several positions of $250,000 and would like to close them out MOC, but just wondering if it's too much size and perhaps I would work the bid/ask instead. Stocks do 1 to 2 mil avg daily vol

That question will depend the volume of the MOC

 

Usually you can expect the MOC volume to be proportional to the average daily volume. For specific MOC volume figures on NASDAQ stocks, try:

http://emi.nasdaq.com/displayfileInline.aspx?file=50&type=index&source=home&tab=openclose

 

Most brokers can sell you this type of information through their analytic offerings.