I have to report that after I became aware of this thread about 2 months ago, I decided to give no-shampoo a try. At first I was using only a conditioner twice a week, but my hair did not do well on it: it was still very dry and harsh. Then I tried the soda for cleaning the scalp, and vinegar for conditioning, and it was the best thing ever! My hair was soft, shiny and felt really clean. I would do soda and vinegar for life if it wasn't that my partner did not like the vinegar smell. So I went back to trying conditioners, and I found one made of hemp oils that my hair took to it. I too prefer the smell of it rather than vinegar.
Regarding pimples on the scalp, I get them too sometimes, but for me it started before I went shampoo-free. I actually observed that I get them if I consume spices, or nuts (things I am allergic to). Same with some rushes on my skin. I don't know if it's the case for everyone though, so perhaps looking for a more appropriate conditioner and then observe what happens, also in relation to what one eats, might help find the culprit.
Regarding pimples on the scalp, I get them too sometimes, but for me it started before I went shampoo-free. I actually observed that I get them if I consume spices, or nuts (things I am allergic to). Same with some rushes on my skin. I don't know if it's the case for everyone though, so perhaps looking for a more appropriate conditioner and then observe what happens, also in relation to what one eats, might help find the culprit.