What are the dimensions? The scale note doesn’t really help us. What this plan reveals is your chorus is on 3 sets of risers. Also that it should appear as if the candles are lighting the chorus. I am presuming you have a way to rig the DeSistis from overhead, dropping them to the “correct” height.
Basically you want to rig those front lights so they are the same distance from the people on the top riser as from the bottom. Probably about 45º at the “right” distance. Something like this crude drawing, where each arm of the triangle is the same length:
As for the DeSistis, I don’t know squat about them, but I presume they are photographically as good as the Kinos. You will want 4-banks to get enough exposure at that distance. An arc of fire that mimics the arc of the choir.
The floor plan shows candelabras in the background. If you want black limbo, you would want to remove them.
I’d also add an arc of back lights which will only really work well for the top row of singers, though with judicious spacing it may also have some effect down below. Your choice as to how much intensity you want here. It will help if the choir is not wearing black, but you will have to make whatever they wear work.
Rick Wise
Cinematographer
San Francisco Bay Area
https://www.RickWiseDP.com