My opinion page addressing inquiries concerning clawhammer technique.
To begin with don't make the mistake of getting in the habit of placing the "middle finger over the index" to help "squeeze" the neck. You will eventually need that middle finger free (along with the ring and pinky) to play on other frets while holding the barre with your index.
Try the following technique I've used with my students:
You should no longer be "squeezing" the neck, you should be using leverage (with your thumb as a fulcrum) to hold down the barre, and the other fingers of the left hand should be free to access additional notes as needed! This will feel uncomfortable at first but will become less so as you develop strength in the new muscles you're using in the left hand!
Stick with it and give this method a chance to work; good barre technique is essential if you want to develop the ability to play effectively up the neck.

Thanks... Mike