Good work so far! I might say that the thickness around the t-visor is just fine, there's no need to alter it. Before preparing the helmet to paint, don't forget to add all the physical damages presented in my ESB Stencils thread (the end of the first post). The best way is to use the stencils as a guide (along with reference images from the Gallery) and after a quick size matching between the helmet and the stencil, you can trace the position of the physical damage, then using a dremel or a triangular file, you can add each damage to your helmet.