I think the 4th component of the normal should be stripped completely as it's redundant with the clippos.z value:
https://github.com/dolphin-emu/dolphin/blob/master/Source/Core/VideoCommon/VertexShaderGen.cpp#L390
I don't think it's worth to change the tesselation shader within a frame, so it's enough to lookup such a values in the shader uids. For ogl, the easiest way is to add the tesselation config within the program uid, so it will be inlined in our programshadercache.
https://github.com/dolphin-emu/dolphin/blob/master/Source/Core/VideoCommon/VertexShaderGen.cpp#L390
I don't think it's worth to change the tesselation shader within a frame, so it's enough to lookup such a values in the shader uids. For ogl, the easiest way is to add the tesselation config within the program uid, so it will be inlined in our programshadercache.