I used them for a while; they stopped working so well after about a year when I moved somewhere with harder water. My hair's thick, too, but tends toward oily. My favourites were Mud & Clay, Summer Sunshine, and Chamomile Citrus, so given that your hair tends to be dry I'd recommend not using those ones except when you're washing out lots of oil. I had less volume with them than I do with sulfates, but other than that they were fine. I didn't do an acid rinse, but I did have soft water so it wasn't a problem.
I rubbed the bar from hairline to nape across my head, then massaged it in. I didn't shampoo the length, as far as I remember, just shampooed to my shoulders or so.