This 8:4:2 formula is a tad sourer than the classic sour proportions of 8:3:4 – two parts of the strong ingredient (gin), three-quarter parts of sour...
There's a bit of a kerfuffle on that "other" site about the necessity of an egg white to make a sour a sour. Some arguing that it's optional. Any thoughts?
I personally wouldn't make a sour without egg unless pushed into it by circumstance or at the request of the person I'm making it for, but yes, it is optional, so I have marked accordingly above.