Diamond Greats was produced by a fellow card collector and photographer names Jack Wallin. The set was released in four 100-card series. Each series was made up of four teams, meaning just sixteen teams, the pre-expansion teams, were included.
The cards are the standard 2½" x 3½"....for the most part. Collector produced, it also seems to be collector made, like in his living room. Many of the cards are off centered and many are bigger or smaller than they should be. There were a few that I had to really squeeze to fit into the protective page pocket.
The Cubs are in the second series, numbers 101-125. Though the set is called Diamond Greats, when you see who the 25 Cubs are, you'll come to the same conclusion that I did--this set is mis-named.
One source I read said that the set-maker Wallin used players that he knew he could get signed up for cheap. Doing that compromised the "Great". Ernie Banks is not included but Harry Chiti is.
In fact, there are seven Cubs in the set that are new to my 12,000+ Cubs cards. Thanks to Diamond Greats, I now have a card of Cliff Chambers (lifetime record of 48-53, 4.29 ERA...Diamond Great??)
Go ahead and take a look at the 25 players and see how many you've heard of before. No too many I'd bet.