Paul Rubin was the apprentice of the recently deceased flying legend Peter Foy. Paul left Foy to create ZFX Flying Illusions with other co-founders (I believe).
Cathy tried the ZFX harness and said it allowed her to do several things she couldn't do in the Foy harness. Also, the ZFX trusses took less than half the time it took to setup the Foy trusses.
So, I believe Rigby's several Pan productions allowed ZFX to become a Nationally known flying company in the theatre world. It was their 'big break' - so to speak.
I could be wrong, but I am pretty sure the above is correct.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle