Ah, Calum, I wish I had your guts. It would be quite liberating to not muck about with my damn hair!
Hendrik, it really does seem to depend a lot on skin type, hair type, and water type. Do you get the same thing if you wash in rain-water? I wonder if that affects the itchniess thing. Lyckily, I haven't really had the itchy thing, though I'm scratching right now as I think of it
It's been a month for me now and I've only used water and once a spoon of vinegar in the water. And it's really getting there now. It went through a hideously yucky stage at around 2.5 weeks in and I thought it could never sort itself out, but it really seems to be. GIve it another week and it'll be pretty much back to 'normal' as if I'd just washed it with shampoo I reckon.
Definitely worth the experiment!