From what I saw from your post I don't see anything glaringly wrong. The area of the knees you are concerned with, really study the human anatomy and you will find the knees can have natural roughness which will affect the texture. Same for the nipple. As long as the textures are good in the default body shape that's all you can hope for because as soon as a person changes the shape the texture will change to some degree. And I totally agree with the others, keep at the project.

I must remember to remember what it was I had to remember.