You're asking the wrong question.
You need to ask if everyone is applying them perfectly.
Is everyone ordering the perfect & appropriate piece for themselves?

Look... its a piece of lace fabric with hairs knotted on to it.
There isn't much more to it than that.
You can ponder, dwell, hypothesise until you're blue in the face and several stages nearer being balder.
Or you can invest a relatively small amount of money and try it for yourself.

Because whatever answers you get from other people, it still won't get you any nearer to knowing the answer you need.
The important question is, "Does it work for you?"

I can tell you now that the overall answer you'll get will be that its not "the perfect solution"
A) there is no such thing as 'perfect'
B) The real solution is to not have lost the hair in the first place.
C) Perfection is an unreasonable expectation and predetermines the likelihood of being disappointed.

So the answer you'll get is that its your best option.