Not sure from the video, does the artist look at the robot when painting or at a screen? I feel like it's going to be really hard to paint that slow, so it might be better to simulate the whole thing (which will be way closer to real time) and then reproduce it later on the robot (with some corrections if needed). But simulating might be difficult... or lead the artist to use brush strokes that are really hard to replicate. Cool project anyway! Let us know how it evolves :)

Also just a heads up on the Amanufactory website the font in the Plans section is really hard to read, you might want to check that out ( http://i.imgur.com/Klvmorc.png ).