I don’t think I’ve ever installed a “perfect” invisible zipper. My Achilles tendon is the bubble that wants to form at the bottom of the zipper, I think because the fabric stretches in one direction when you sew the first side of the zipper and then stretches in the other direction when you sew the second side.
That said, my invisible zippers look pretty damn good and by far better than lapped or centered zippers.
Here is the best tutorial I’ve ever seen on inserting an invisible zipper. It has clear pictures and instructions.
One thing I can add, if you can’t find the perfect color zipper, the zipper stop (the only part that shows on the right side) can be painted with model car paint available at hobby and toy stores. This gives many more options to match the color of the zipper stop to your garment.
Here’s the article: