Actually the whole which lace thing or what kind of hairsystem thing is pretty simple. It always depends only on what your expectations are. Example: if invisibility and undetactability count most for a person than there is no alternative as going with the thinnest lace available. Of course that would probably mean you have to go with approx. six units per year, but hey, that's the way it is and nobody in the world can change that. Every thing else in this particular case would mean to compromise and to lower your original expectations.