My guess is you are wondering about putting size 12 liners in a size 11 boots. That looks like an experiment. Thinner soxs might allow a smaller boot also.
http://www.dryguy.net/PRD_TF.htm liners may offset a less warm boot if that is an issue.
Some bindings have risers that elevate the boot hangover area for more clearance. These might actually allow faster control with the toes. When entering "snowboard binding power risers" on a search engine, many results for options occurred.
As far as issues with boot overhang drag, the snow conditions have a big impact. Huge Utah type pow might feel like a slight application of the brakes; bullet proof ice body dragging turns, will lift the edge off the ground (this is kinda catastrophic)
Shoe goop properly applied, repairs nonwanted results on boot shaving experiments. Again this shaving can negate a warranty most likely.