Hi,
I just completed my M116 set a few weeks ago. Was a very fun project.
As for where to look to find them. Ebay, here, and other auctions on this list:
http://www.net54baseball.com/forum/c...tagelinks.html
You can use this link for a great checklist that ranks the cards. (8 hardest to 1 easiest I believe)
http://www.oldcardboard.com/m/m116/m116SearchIndex.asp
Good luck and welcome to the board.
Robert