Full disclosure first: I'm not going to be doing the mystery. :-)
I've been a lurker for several years now and a number of people do choose a smaller version of the project as a jumping-off point and that might be something that appeals for WMU, Quossum and others who are fence-sitting. It seems if you make about half the units as you go along, when it's time to put things together it only takes a little tweaking and going back to make a few extra units to make the pattern work (this also applies if you want to make the pattern rectangular or even larger).
Just a thought. :-)