The distance is approximate. I took the bindings off one ski and measured with templates. It looks to be around 20mm or so. I can get an exact measurement but I don't think it matters much, Put on template, drill holes mount bindings, go skiing. The idea was what Eleeski said, moving the binding, which will take all of about 10 minutes on my milling machine, would allow me to go forward and back with a greater range. I wish Eleeski did not send that link. That level of technicality is way beyond my scope. I'm 66 years old and pretty much suck at skiing anyway, so a few mm will not matter all that much. It just pissed me off that the lines didn't line up. Now I am way overthinking this and my head is going to explode. Poof.