How can I divide U tiling sizes of spline meshes by area of polys they are on?

I don’t want streched textures on my spline meshes, I don’t want to use fixed size distances between spline points and I don’t want to use too many material instances for all of the spline meshes because I have to save draw calls by merging them, using seperate materials is not a solution in this case. I also don’t want to edit kilometers of spline meshes on third party 3D programs.

What should I do? I can’t believe Unreal hasn’t got a solution for this.