Thank you :) Hard to say, you can peer into the WIP thread, this may tell you a bit. I find it quite fast for me given it's complexity but I always sit over artworks long and nitpick details, still work way too slowly. I need to record time one day, I'm curious myself. Anyway sets of hours in several days (like from evening till dawn as happened on my recent piece, not good habit). And just yesterday I did more colour corrections, while a few days ago I rotated the figures a bit (image resubmitted).
My works are never really finished ;)