Shriketastic's GM here.

He came to me last night with the idea for making a rote for this purpose, and I just wasn't sure of how to adjudicate it, so I asked him to post a thread about it here, to get your input.  Perhaps I should have just posted the thread myself.

After reading the input, I'm definitely coming to the conclusion that targeting just the spirit would be outside the realm of Evocation, which is kinda where I was leaning to begin with.  Thank you for the input.