I'm not certain, but I would have thought that without mods, max is 28 on a huge map. There are 4 land lux per continent, and 4 sea lux. A huge map has 6 continents. 4*6+4=28. I was under the impression that city state and great merchant lux don't count for Aztec bonus. But maybe I'm off? Or maybe you're using mods affecting the number of lux on the map?