gr.king

Rather than struggle and frustrate yourself trying to use rubbing down paper of various sorts in the awkward corners of a full 3D print, try a small, sharp, flat edged scraper drawn lightly and repeatedly ALONG (rather than across) the printing ridges. It will take off all of the peaks, you can feel (and stop) when you reach something like boiler band, and you can get into all of the corners. It worked well for me on Bill Bedford's O4/5 superstructure. If I were you I'd stick to a body that's largely one-piece if you possibly can in order to maximise the advantages of the 3D print technology.

That definitely looks interesting, and very promising. Are you prepared to consider offering N1 prints to other modellers?