God it almost does look like those bindings are too big for your boot, but I would imagine you're right in that a medium wouldn't work on a wide board. Are you sure the ones you demo'd were larges?
I was told they were, we had to adjust the straps several times to keep them from bottoming out when tightening, so yeah! Pretty sure! And I didn't notice ANY ride performance issues! Board didn't feel squirrelly or radically different when riding.
I Just noticed that the bindings were way more comfortable than my old Cartels and actually, my boots didn't lift/rise up & ride the outside edge of the bindings base whenever I tried to Butter! (...my old Cartels let my boot lift in the bindings and bottom of boot was on outside edge of base no matter how tight I strapped in!) With the New Cartel's, My boots fit better in the bindings, but the bindings apparently don't fit my board??? Cannot center them to even out overhang!
Does any of that make sense??
Now,.. I have NO idea what disk plates were used for the bindings I demo'd on my Arbor! The Cartels I rode on the Burton boards I demo'd were the EST (...or channel?) Not sure what was used for mounting them on my Arbor!
Oh yes, Btw my Old 2010/11 Cartel's are Large!!! They work just fine with this board & boots! (..just not as comfortable!)