It's common in character work to split the head off into its own texture sheet so you get more fidelity on the face. Doing that obviously means it's going to be in its own TextureSet in Painter. How would I go about avoiding an obvious seam on the neck, between TextureSets? Let's assume the character is shirtless and there is no way to hide the seam behind anything, so it's a pretty unforgiving situation. AFAIK you can't paint across TextureSets or use the clone stamp tool across them. The two workarounds I'm aware of are:
1) Get it look as good as you can in Painter, then export all of your textures into something like Mari or Mudbox to do cleanup on the seam.
2) Put both the head and body on one really big sheet (4k I guess since that's the current limit in Painter) then reproject onto the separate sheets at the end.
Both sound like kind of a pain though, so I'm hoping for better ideas.