As soon as it's on your noggin it'll disappear. No such thing as totally invisible, but the more you practice the better it will look.
Look at my first pics which I was pleased about, but not over the moon. Look at my last post 2 months later. Now I'm over the moon.

It's work. People shouldn't pretend it's a breeze, but it's the closest thing in the world to getting back a full head of hair.

Learning how to deal with the glue will make all the difference. The lace will sit in it and disappear when you get it right. Took me a month to believe that thin layering the glue, letting it dry and then relayering actually works!
Good luck. Nothing ventured, nothing gained.