Gurkenglas comments on I made a card game to reduce cognitive biases and logical fallacies but I’m not sure what DV to test in a study on its effectiveness.

[Gurkenglas]

you’re getting fleeced, go to a print shop and print some cards on thick paper and cut them with their cutting tools. if you print 9 decks side-by-side on a stack of A4 paper you might not even need to measure.