[wrapperguy]

My father and I have been collecting this set for years. We originally just went for one example of each player, whether it had writing or not at the bottom. Then, for some unexplained reason, we decided to go for a "no writing" set and a "with writing" set and started going after the yellow prints also. Still missing about 7 of each category. You are correct that the yellow is considerably tougher though I cannot give you a ratio. When looking at the Old Cardboard checklist, I can say with certainty that a Ruth yellow does exist. I saw it at the Cleveland National in 2009 (and passed on it - oops!). Good luck with the set. I have about 40 dupes if you are interested.
Jeff