I'm to chicken to do that, so I do the broomstick method or the co2 chamber. When you put your ad on Craigslist, did you put it in the livestock section? That's where I put mine.
I just looked at the link you posted and I think this one has better pictures of the technique.
https://mikethechickenvet.wordpress.com/2017/02/16/euthanasia-for-backyard-birds/