The organ of Santanyi is a marvelous historical instrument by the famous Spanish builder Jordi Bosch, restored by Gerhard Grenzing (1984-1986).
It is a special instrument all around, but one of the most prominent assets is its enormous Ple // Mixture of 2' 2/3', 22x left hand and 4', 25x right hand.
The registration for this piece is:
Flautat Major (LH & RH // Principal 16')
Flautat (LH & RH // Principal 8')
Octava (LH & RH) // Octav 4' (4' II, 8' + 4' + 4', III)
Ple (LH & RH)
you can hear it in all its splendor in this piece, which is not a Tiento de Falsas itself, but based on one by the great Aguilera.
For those interested: the link to the Aguilera piece itself is here:
https://www.contrebombarde.com/concerthall/music/33363