I think that many get too het up about the rubber ruler. I use the LGB DR stuff, plus I now also have the Piko Harz Kamel. Though I always knew the scales were mixed up, it does not worry me overly. For instance because LGB never got around to the Harz Mallets, I happily use the Sachen Meyer in its stead. I use both the Green and Black one as my Mallets. Now I know that they are wrong, but because LGB monkeyed around with the scales, the Narrower Gauge Sachen looks OK alongside all the Metre gauge Harz stuff. Plus the Piko Kamel sticks above the coaches to a satisfactory degree. To me because I am into Timetable Running more than running a ruler over the kit I am happy with the way things are.
On a side tack I also love the Irish railways, the L&LSR in particular. I run an L&LSR Timetable on my line with a friend using all the DR Harz Stock. We use the Harz (LGB) 2-10-2t to represent the 4-8-4t that the L&LSR had. Suspending belief a bit in this way can actually make you seam that you really are in Ireland back in the 40's. yes I know it is imagination, but that is the sort of thing that gives us hours of fun. When I can get sufficient operators together then I will also run a Harz timetable too.
So rubber rulers, well I have met too many P4 wallers to worry about it overly, as a good friend of mine used to say "Life is too short to stuff a Mushroom".JonD