Lucid OBE/ESP experiment using playing cards

As Laberge says that ESP abilities could be improved in LD, I find this Lucid Laboratory Lucid ESP experiment very interesting.
[url]https://community.ld4all.com/t/lucid-obe-esp-experiment-using-playing-cards/10880/1]

But why not use the 5 ESP Zener cards ?
https://www.mdani.demon.co.uk/para/zener.htm
Perhaps, since their symbols are simpler than game cards, they are less likely to change during the dream ? And it will be simpler to compute statistics, too…