I tie one that is pretty close to what you are doing except I like to float a little...for fishing in thick grass, so I am using a clipped deer hair body. I don't add any weight. It just kind of sits there in the grass. And I add a 50 lb mason loop weed guard. Can't move it too much or it gets hung up anyway. the spartina grass is so thick. But when you get it where it is supposed to be...
I also tie one with a dumbell eye for fishing over sandy flats in Pamlico Sound. Pretty much the same. I am going to try your hackle crab for that, definitely a lot easier to make.