I don't know what to make of the odds. Baseballcardpedia says the sketch cards were 1:38 packs.
https://baseballcardpedia.com/index....8_Stadium_Club
But while it says "?" for number of cards in the checklist, if you scroll down it says there were 100 of them. If they are 1/1s, then the odds don't make sense.
Sketch cards are way undervalued compared to other 1/1s, but I like them.