Spanish music theorist, organist, and composer Tomas de Santa Maria (ca. 1510-1570) in his work "the Art of Playing Fantasia" (Arte de tañer fantasía, 1565) presented the following table:
So it appears that the "good" fingers for Santa Maria were 2 in the right hand and 4 in the left hand.
In today's piece for sight-reading, there will be plenty of places to apply paired fingering - bear in mind that these shouldn't necessarily be complete scales - excerpts of passages in step-wise motion would work for this type of fingering, too.
Here's the score of Duo I (p.1) by the famous blind Antonio de Cabezon (1510-1566) who was a contemporary of Santa Maria and the first significant Spanish Renaissance organist and composer.
In this piece there are only two voices - one for the right hand and one for the left hand. The piece starts with the note-against-note counterpoint in whole notes (m. 1-9), then moves in half notes (m. 10-18), then - four notes against one (m. 19-30).
From m. 31 Cabezon employs points of imitation when one hand plays a subject and another answers at the interval of an octave or fifth. At first imitations are played in half notes but later the movement intensifies and Cabezon uses more and more quarter note motion.
As you play this Duo today, take a slow comfortable tempo, use articulate legato touch with small breaks between each note, keep your fingers in contact with the keyboard and play on the edge of the keys.
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