Oh, see, now that is NOT fair. Those are freaking brilliant, and I can't choose.
If I HAVE to choose, I would ask for the black backs because of reversibility, but I'd also ask for a card that has the circle on it, like a double-sided gaffe card?
And maybe if you wanted to do a version of the Sakura circle on one side and a Clow circle on the other, so you could turn the card one way or another depending on which version of the cards you worked with?
... I might actually be sort of obsessing over this whole deck now. Seriously, it's brilliant please make it available for purchase I need it.