One of the reasons that people go on about the metric system is that it so standardized.......in my experience there seems to be either a significant growth in the size of a millimeter or a problem with its application in the world of toy soldiers. Thus we are forced to use highly unscientific instruments such as the MK. I Eyeball when measuring our models. My work around is to simply stand them up side-by-each and take a look. It has worked well for me in the past so I present a photographic record of my efforts for perusal .