"So I'm looking at a pair of bindings that will need to get adjusted for new boots. So let's say there's an inch of travel left on the heel piece in the direction I want to go. How many boot sizes is that?"
An inch is 2.5cm, and 1cm is usually one full size. that would mean that you have 2.5 full sizes of travel.
What bindings are they? Are they mounted on your skis, or are you looking to buy bindings?
In that case, almost all companies have different drill patterns. Tyrolia is the same as fischer and 4frnt(now), Look is the same as rossignol, Vist is the same as 4frnt(past), amplid, nordica, and so forth. As in a salomon binding doesnt have the same drill pattern as a rossignol binding.
With my most sincere regards,
Golden Wheelchair Nominee- September 21-28