Thanks woodie. Experimentation with store bought supplies...an earlier poster suggested building up under arch with handlebar tape...is not much different than P.I. or Shimano selling their adjustable arch height insoles. Filling under arch void with a firm yet compliant material. Some believe firmer is better. I have skied with rigid feet insoles molded to my feet which were super comfortable...so there is a bit of an analogy to saddles...firmer can be better as long as there is fit agreement. Shoe makers sell low arch inserts because a flat foot wearer will suffer with too much arch support. Arches too high supinating the foot is no good either. Fitters use trial and error as do many cyclists who know intuitively after testing whether their arch is under or over supported. I have done what you propose with both ski boots and cycling insoles...cork with its firmness yet some compliancy is popular. But there are other materials as well...closed cell high density foam...even old shoe insole inserts cut in the shape of an arch and glued or 2 face taped under the arch. Thanks again.