I use Dr. Bronners without issue. Since you already have it, dilute it 1/12 it's strength and give it a try. I put my solution in an applicator bottle with a tip so that I can concentrate it at the scalp. I rub it in with my fingertips and then rinse really thoroughly. After that, I separate the dreads in the shower while they are wet or they dry too fast once I'm out. I will occasionally use ACV rince with lavender, tea tree and rosemary.
Once you've washed a couple times with Bronners you will have the verdict on whether or not it is working for you. If it feels greasy then switch to the shampoo mentioned above or do a BS/ACV wash. It doesn't hurt to experiment until you find something that works with your hair type and areas water.
When you wash they will be a bit fuzzy which is totally normal. Natural oils on the scalp can cause the hair to be too slick to dread properly/quickly so washing regularly is a good thing. I wash about 3 times/week depending on how much I feel that my scalp needs to be cleaned (sometimes hiking makes me a Sweaty Betty.)