I've been curious about this for some time. They are called 35mm and the comany says they are measured Sole-to-eye like other miniatures, but I've never seen a picture of one next to a ruler. The company-supplied picture is woefully inadequate, lacking any measuring tool, not labeling of the reference lines and failing to even have the various figures feet on on the same plane.
My curiosity is mostly about whether they will be at all compatible with my RAFM Airship Pirates (Kickstarter) when they arrive. So far the Airship pirates I've seen seem to be solidly in the 30-32mm (Sole to eye) range.