Potters & Sculptors - Making Rock from Mud
George, I don't have the recipe for SCM close by, but if it has potash feldspar, try subbing Neph Sye for the Custer, or other spar. That can lower the maturation of the glaze by two cones. That's one quick fox to try. If that isn't enough, you can lower the clay content by 5, for instance, and up the frit by 5.These are qucik fixes to try without having to run the glaze through a glaze chemistry software.
Often, glazes listed as cone 10 for instance, may actually work one or two cones lower or higher, and the Neph Sy substitution may be enough to reach a desire result.