You know I'm too lazy to do sponging, so I have my own technique for holographic gradients. This is actually very simple. I started with two coats of Butter London Nail Foundation to cover VNL (visible nail line), because after using another similar Glitter Gal (Wisteria swatched here), I realized this was the best way to achieve opacity without having to use so many coats. Then, I applied the lighter color, Nude, at the base from cuticle to tips up to 1/2 of the nail. One by one I finished with the darker color, Flawless Pink, from the middle of the nail to the tip. For the second coat, I applied Nude at the base from cuticle to tips to 2/3 of the nail. That is, covering up a little bit of the first coat of the darker color to soften it. Then finished with Flawless Pink on the remaining 1/3 of the nail, at the tips. This can be done with any holographic, since this type of finish allows for mistakes to be covered by the rainbows.
Butter London Nail Foundation Basecoat
2 coats Glitter Gal Nude (base)
2 coats Glitter Gal Flawless Pink (tips)
no topcoat in these pictures