Mark...cool transparency & progressive proof!
Here are the two versions of the Ripken Thom McAn discs I mentioned in that 1993 article. The blue disc I obtained early on and for awhile thought that was the only version.
Interesting story was at some point I was introduced to a collector who informed me about the Ripken yellow version and was trying to obtain the entire set himself (with all color variations) who traveled often on business. What he did was simply buy one pair of Thom McAn shoes and in his travels and he would exchange that pair of shoes at one of their stores (wherever his travels took him) for another and get two new discs.
He promised me that if he ever gave up trying to complete the set that he'd sell the yellow Cal Jr. to me. Fortunately (for me anyways), he gave up on trying to complete it:
As I mentioned in the article as well these discs can be differentiated from the Subway discs in that these have the Thom McAn/Jox logo on the back.