Robbie vs notation

It's getting close to the end of the semester and I'm just putting the finishing touches on my piece. This piece was definitely quite a struggle for me to complete. So many times I contemplated scraping the entire composition and starting something new, but in the end I think I came out with something that is very contrasting to the rest of my portfolio.

Right now I am trying to pick out the best notation and symbols to best explain my piece to the performers. I have a acquired a book from the QEII called 'Music Notation in the Twentieth Century' by Kurt Stone which contains a lot of notation for extended techniques that I have been finding very helpful. I'm still trying to decide which would be the best way to notate the vertical bow scraps of the cello. Any suggestions would be greatly appreciated.