The first head of Kathy's Waltz is actually played in 4/4. Then the solos and last head are in 3/4.
In this arrangement, to simulate a ritardando in the Coda I've doubled the time there to 6/4. Also, as one cannot write polychord symbols in iReal Pro, I've just written "Polychords" over the applicable chords.
The change from 4/4 to 3/4 is not accurate, as Brubeck specifies that a 3/4 bar should correspond to a quarter-note triplet in 4/4. But that would require increasing the tempo mid-song, which iReal Pro cannot do. So to compensate, I've just indicated a faster tempo for the 4/4 section than in the original.