If you were really lucky and bought during a one minute window 5 minutes before the close, you might have made 15 cents. I got some of that, but paid up for the rest (my sell order was already in). Bought right before the close and lost a dollar 30 seconds later on the MOC print. It was obvious that there was an imbalance to the other side because so many people were playing it. It was only a week after the GS moc and I think that attracted many more players. I've done them before and never made more than 20 cents or so, it's pretty much a crap shoot. The play now is trading the action into the close as everyone positions themselves.
you can find info about additions at http://www.spglobal.com/ www.nasdaqtrader.com as for MOC orders, some times they work and some times they don't. GS, when it was being added a few weeks ago, closed around 72-73 and changed and printed 77 if you had MOC orders. Nadaq additions are more fun to play if you like some excitement, an example would be EBAY.