I have it applied to both my Ruger P's. First time I had the Wife do it since she is much better at painting.
Second time I did it. It was really quite easy.
I used a toothpick to pick up a drop of paint and dabbed the deepest part in the sight. Next drop I just touched the top of the first layer and kept doing this until the paint was level with the surface of the sight.
Continue to hold the gun barrel down for a few minutes. The paint will level off and concave a little. Don't worry if you get a little bit of paint on the surrounding area of the sight. It is a rubbery substance and will peal off with light pressure from your finger without disturbing the paint covering the white dot.
A word of caution. This stuff rubs off easily from hard surfaces but will stain fabric.
I don't know if you purchased the ghost glow, I did and didn't like it.