Just to update this thread I managed to exchange for mediums.
My size 11 rulers are snug, but fit well.
If you run a size 11 with reduced footprint you will NEED MEDIUMS
for most boots. Definitely check before you buy.
This is because the new reflex bindings don't allow for as much centering adjustment
as the older non reflex binding disks.
My size 11s fit the straps just fine on the large, but I cannot center them on my proto CT.
Burton Japan totally helped me out with this and big props to their customer service
I would personally like to see them go a step further and make a little note in their size chart about reduced footprint sizing.
Several people PM'd me with the same problem and they were previous (non reflex) burton binding owners.
Seems people don't worry (including me) about the fit, they assume the adjustments will be the same when buying the same brand binding for use on the same board with the same boots.
While this is a mistaken assumption its an easy one and obviously a fairly common mistake. Maybe a little note on the binding chart would be a good idea?