What haircut would help thin tangled hair?

My hair is very thin and ridiculously tangle prone, to the point where it would take me an hour to get all the tangles out, and i would end up yanking a lot of hair out in the process. My hair is about 8 inches below the shoulder, sort of mid boob length. I cut about 4 inches off a while back but it didn't help with the tangles/flatness as much as I had hoped. I don't want to cut too much length off, as long hair suits me, but I am open to taking off a bit. I was thinking of getting about an inch more taken off. Is this enough? Or is more optimal?