@gloriouscow that was kind of a pain when I was doing a similar thing, are you chaining two dma channels? Iirc that's fast but I couldn't make it wait for the frame buffer to be ready so there was some tearing. I also didn't have a lookup table so that would complicate matters
Here is a writeup (not mine) of some PIO/DMA graphics gymnastics that does involve a lookup table, maybe some of the tricks will be useful: https://dmitry.gr/?r=06.%20Thoughts&proj=09.ComplexPioMachines
Good luck and I look forward to seeing the updates!