OT has a neck designed specifically for the DX19 head on his site below. Looks like a huge improvement.
https://www.shopotcustoms.com/product-page/dx19-specific-neck-upgrade-hot-toys-the-dark-knight-rises-batman?fbclid=PAAabKNTs_ndyjwLgR4JhvfulLgEFNuBHemoTZexkF3PB-kui8WfxC8wHVklg