FYI to anyone finding this post via search, since it’s still a top result for “PixelBlaze Palettes”: This is now natively solved in PixelBlaze.
You can check out a post about how to use the new Palette functions here: How to modify existing patterns to use Palette functions in v3.30 - #10 by ZacharyRD and you can read the release notes about it here: V3.30 Release - palettes, Perlin noise, and much more! – if you’ve always wanted FastLED style palettes in PixelBlaze, you now have them! Enjoy.