couple options. if you have a little extra toe room in your boots, you can apply a layer of silicone to the outside of the liner. i remove the toe portion of my footbed and blend it down to make room. works really well.
but the reason your bangin the front, is your instep area is too large (where your foot and leg meet in the front). your shop should be able to build up some posting foam on the outside of your liner to take up the volume. with new, unblown out boots, prolly not much of a problem.
other option is to shim up the footboard, to downsize the volume
custom footboards will def help as well, specially if you have flat arches.
