Original clef version in F has basses on a low F and tenors up to a high C. https://www.cpdl.org/wiki/images/c/c7/Palestrina_Sicut_cervus.pdf

There is a CPDL version which says it is down a whole step to E flat - but the link is not working. However you can take any one of these, download the XML file onto something like musescore, and transpose yourself as needed. https://www.cpdl.org/wiki/index.php/Sicut_cervus_(Giovanni_Pierluigi_da_Palestrina)

In any case the lowest bass note and the highest tenor note are going to be two octaves plus a fifth apart.

There is an arrangement of the piece for smaller choirs available here for SSA which you could try an octave down. It's designed to be gentle on ranges. Obviously a lot of the full effect is lost, but it might work for you. https://www.alfred.com/sicut-cervus/p/00-35525/