I found summer the easiest time to transition, b/c I could slick my hair back and wear it up, and no one would know it was greasy rather than gelled back. Gross, I know, but there is a transition period that is really hard. Also, I found the more BS/ACV I used (both quantity and frequency) the worse my hair got. I finally realized that if I just left it alone and used water-only to "shampoo" my hair, the roots are far less greasy than with BS/ACV.
What I would do is clean my hair with a tiny bit of BS just on the roots, rinse with diluted ACV, and then do water-only for a couple of weeks and see how it goes. It can't get too much worse, right? And if your hair is long enough to pull back/up in a pony tail, it won't matter much.
I've found that the key to water-only for me is that you have to scrub your scalp just like you do with shampoo and conditioner, not just wet your hair down. Also, I turn my head upside down while scrubbing and rinsing, to get as much of my scalp/roots clean. Then I rinse in cold water upside down. It gives my hair a lift and keeps the grease from weighing it down too much. (I have wavy hair, YMMV if your hair is straight/thin/fine.)
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