I cracked open my box and tried my KMC Perfect Size Sleeves (89 x 64 mm)
They fit, well, perfectly. Note that I do mean "perfect" - as in "the top of the sleeve is exactly level with the top of the card." Whereas my Magic cards have about a half millimeter of space to spare at the top.
But this answers the question: they are just a tad taller than Magic cards. I may bump up a size from the Perfects, to avoid bending or scraping the top of the card.
It's also worth noting that the cards barely fit in the box insert unsleeved, so you'll want another storage solution if you sleeve. I plan on putting the cards in deckboxes and using small tupperware-style containers for the cardboard bits.