This is a full Spark project that uses the native UI picker to select LUT effects, and transitions between them with an animated gradient mask. The direction of the animation will correspond to the movement of the picker. Out of the box, this effect supports up to 10 LUTs.
You can edit the patch graph to customize the behavior in a few ways: the size of the transition gradient, animation curve, transition duration, and of course the number of LUTs and the LUT order. The simplest way to change the LUTs is to simply replace the textures. If you want to use your own file names, you'll need to update texture name references in the script. Similarly, if you want to use picker icons that aren't the same as the LUT textures, you can change the names in the script to point to icon textures.
This project can be used as a starting point for your effect, but it also comes with ARP patches so you can easily integrate it into a pre-existing project. It requires v80+
Full Spark LUT swiper project