yes 2 cards are converted to a letter pair using a nice mapping.
9H-6D-KS-QC-4D would be memoed with six letters:"9-Hearts-or-Clubs" (26 possibilities)"6-Diamonds-or-spades" (26 possibilities)'King-Diamonds-or-spades" (26 possibilities)"Queen-Clubs-or-Hearts" (26 possibilities)"4-Diamonds-or-Spades" (26 possibilities)"RED-RED-BLACK-BLACK-RED" (32 possibilities),Which would pretty easily fit into a letter-pair memo (if you added a few more letters for the RED/BLACK parity).
As in, you group cards into "pointy" (diamonds/spades) or "rounded" (hearts/clubs). You memo:"9-Rounded, 6-Pointy, King-Pointy, Queen-Rounded, 4-Pointy" then "R/R/B/B/R" for your five cards. So, 3 letter-pairs per five cards meaning you can memo a deck of cards in 30 (+3) letter pairs, Which is somewhere between 4BLD and 5BLD in difficulty. It's not the most efficient method, but likely the "easiest" if you can already do 5BLD. 60 seconds should be achievable with practice, even with a double-pass.