You say - "full size" as in actual size...?:blink: 35' L x 13'W...:blink:
Why can't you place a grid on a smaller print - use a ratio and transfer that to your work area,,,,,
Just a thought,....
printed paper template, or shooting laser from the floor or...
layout on the/a floor, and construct the framing in segments that can be flipped, hoisted and secured on the ceiling. The hardest part is getting the ellipses right. Certainly could paper or Masonite/yucca board template them and transfer to the floor 4x using the same template... Probably what your guy is thinking, I hope. So all you really would need printed is the ellipse, if you have access to an area where you can pull 22'.
Yes I would stay away from the string method on something that long, the string does stretch and makes it impossible to form a smooth arc.
What I've done in the past is layout the arc on Sketchup and take measurements on a grid layout, then transfer that to your wall/etc. I used 3" grid spacing for a 19' arch.