I had intended to start my own grand tour with a design that reminds me of the one you posted. I only have the first stage in orbit right now, so changing things won't be too much of a problem. I have learned that I probably don't have enough fuel though! Currently I have plans for six big red tanks of fuel running eight nukes. I have some skipper engines that will be attached at some point in case I need a lot of thrust right away. I've never made it past Duna, but I have learned that nukes are very slow! Much like your design, I have intended my ship to be completely robotic in assembly. The concern I have is if I will be getting enough solar energy at the outermost planets. I don't see any way to shut down the robotic controls, so they will be a constant drain on energy.