Fingers acaan deck ("number to card").
This thread is much simpler than my other thread about the fingers method.

This stack is based on the following six positions and cards:
12=3H
13=4C
14=5D
23=5C
24=6D
34=7D
Rule for above is to mentally add the two numbers to know the card value and then just use the second digit to know the suit (SHCD) of the card to fxxxx.

Fingers acaan deck ("number to card"):
XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, 3H, 4C
5D, XX, XX, XX, XX, XX, XX, XX, XX, 5C, 6D, XX, XX
XX, XX, XX, XX, XX, XX, XX, 7D, XX, XX, XX, XX, XX
XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX

Having two of the above decks the magician can do a similar trick as seen on Penn and Teller:

See the 2:30 mark thru 7:00 minute mark:

https://youtu.be/AexoXU3y3sc

Magician says "put either deck in your pocket".
Magician then does the fingers number fxxxx:

"hold up a different number of fingers on each hand, we will make the lower number of fingers the first digit".

The Magician opens the second deck and spreads the deck face up on the table showing the deck to be well mixed but then picks it up at the same time casually cutting the proper card to the top of the deck.

The magician then has a spectator cut the deck (criss cross fxxxx).

Magician has the spectator take the first deck out of their pocket and deal down to the "fingers" number. Eureka!

Hmmm, since this "Fingers Acaan deck" is totally focused on doing the "number to card" calculation and nothing else we can loosen up the rules for the spectator and instead of saying "we will use the lower number for the first digit" we can give them the choice of which hand is the first digit by adding some more force cards in the appropriate places and still maintain the same simple calculation rules.
12=3H
13=4C
14=5D
21=3S
23=5C
24=6D
31=4S
32=5H
34=7D
41=5S
42=6H
43=7C

Now the stack will look like this:
Fingers acaan deck ("number to card" 12 possible cards):
XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, 3H, 4C
5D, XX, XX, XX, XX, XX, XX, 3S, XX, 5C, 6D, XX, XX
XX, XX, XX, XX, 4S, 5H, XX, 7D, XX, XX, XX, XX, XX
XX, 5S, 6H, 7C, XX, XX, XX, XX, XX, XX, XX, XX, XX
Of course both decks should look like this.

With the above stack the magician can give the spectator the choice of which of their hands will represent the first digit of the number. Example: let's say the spectator presents 3 fingers on one hand and 2 fingers on the other hand: The magician can say "do you want this to be 32 or do you want it to be 23, it's your choice".

With this stack just be careful to use the second digit in the number they say out loud to determine the suit (not necessarily the highest of the two digits as is done in the original six possible force cards stack).

Note that I also thought about adding 11, 22, 33, 44 and their corresponding cards but that would start making noticeable patterns therefore the magician still needs to say "hold up a different number of fingers on each hand, no thumbs".

This is so easy. Example they say the number is 32 therefore the magician thinks 3 + 2 is 5 next the number 2 means the suit is hearts.

Thus the magician knows to fxxxx the five of hearts using the second deck.

Then the magician has them count down to the 32nd card in the first deck.