How perfect is the best adhesive with broken glass? (imperfection approx zero) and is it possible to have a perfect restoration?

I would think the quality of your restoration lies more with how broken the glass is than with the glue you're using. When you say "imperfection approx zero", are you saying there are absolutely no small chips of glass unaccounted for? That each piece of broken glass will go back together again without flaking or otherwise showing a break?

 

Also, when you ask about a "perfect restoration", do you mean aesthetically perfect, functionally perfect or both? I shouldn't assume the glass is clear but does that make a difference? Is this a window pane or a blown-glass figurine or lamp fixture? Are you worried the adhesive would let water or air come through the breaks?

The uv glue can stick broken glass.