Drawing with white pens

I've never drawn with white pens before. But I recently received some grey and cappuccino paper from Hahnemühle, so I was eager to test them out.

As you can see in the image below, my felt-tip markers aren't opaque and have a chalky feel to the strokes they produce. In order to make the colored area more white, I had to apply several layers of ink. Nevertheless, they offer an interesting effect against dark backgrounds.

I still need to find a white pen that is more opaque and precise, probably a gel ink pen with a metal tip. Fortunately, there is plenty advice on the Internet, considering this guide by Jet Pens thaf I found very helpful.