I might just have to try out Incendia sometime. However, I am still trying to figure out what to do with Apo. Great job, love the colors, and the spirals are definitely very clean and the sphere's add a nice texture to the overall picture. Finally, when you are zoomed in I love how the details of the little rings mold it together.
Oh wow. That is a LOT of time. I don't think that I could handle that. I just did a render with Apo that took just shy of 3 hours and that is a density of 2k for a 2560 x 1885 image. I normally keep my default to 10k, but decided to give this render just a bit more clarity. Although, I wonder if there is a point of diminishing returns once you go past a certain density.