I am trying to minimize texture seams and distortion in order to use a tiling detail normal map on top of a diffuse map on a humanoid mesh for use with Miku Miku Dance. I believe that if I use two different UV maps sharing the same silhouette, I can avoid visible seams and that the distortion will be acceptable. I have separated my model into a front and back half (two different objects) rather than seaming it in Blender while trying different solutions.
Because the front and back half have dissimilar surfaces (but share a border), Blender UV maps them to different silhouettes, which will create visible seams on any map tiling over their surface.
Is there some easy way that I can get Blender to use the same silhouette for both halves? I would prefer not to join and reseam my mesh, but if that's necessary, I'm willing.