Hi Craig,
E98 is my favorite of the candy sets and I had a blast getting all of mine. I'm still three short and don't see myself finishing the set any time soon as the three I need (Cobb, Wagner and Young) are all out of my price range, but I'm super happy with what I've accomplished. They aren't the nicest looking in some cases, but they all mean a lot to me. I'll likely upgrade several of them over the years though.
As far as color scarcity, people are correct that it is by a player by player basis, but red is definitely the most common these days. I believe blue is the hardest overall though. I only know of three blue Lajoie's at this time, although there are certainly more out there in private collections. I just only know of three.
The other very important thing you should know is that there really isn't a Cy Young in this set. Others may have a different opinion that mine, but the fact is the Young in this set if a card of Irv Young, not Cy Young. That's not up to debate, however some folks still consider it a Cy Young card. Not me. So, if you want to complete the set, be prepared to pay Cy Young prices for an Irv Young card. I know more than one person here that had a difficult time doing it, and one in particular that did it four times.
Here is a composite of my current set as it sits. As well as a handcut scrap that I have.
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